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I'd like to give you a happy fun thought experiment to chew on.

It's 2016. And it's been a bad year. Let's imagine that it's about to get infinitely worse for everyone, and by December 31st, 2016, the human species is extinct. Cause: something minimally disruptive to the rest of the biosphere. (A very tightly targeted human-specific military bioweapon gets out and proves to be unexpectedly deadly: say, an IL-4 expressing poxvirus that goes above and beyond.)

Earth abides, of course, and without humans life goes on.

Let's ignore the immediate aftermath (1-1000 years). Nuclear reactors scram automatically, grids shut down, there are various nasty industrial accidents from unattended plant, and then the atmospheric carbon pulse continues and is joined by large-scale outgassing from the Siberian tundra and possibly a crash in hard-shelled ocean dwelling species due to acidification. Global mean temperatures rise by roughly 4 degrees celsius (hey, we're not pumping any more CO2 out!) leading to considerably worse weather events and various ecosystem changes: the ongoing mass extinction event continues to coast on momentum during this period as more specialized species fail to find new niches.

(Noteworthy exceptions: rats, cats, dogs, pigeons, grasses, and probably goats are almost everywhere, thanks to human activity. So are a bunch of other species, but sheep, cattle and horses are less prepared to go feral if you abruptly remove all human intervention. Nevertheless, there will probably be new ovine and aurochs subspecies in the wild in places far from their original point of domestication by the end of the 1KYa marker.)

So, let's look to the long term.

Vertebrate life on Earth dates back roughly 525 million years. Our sun is gradually brightening, and over the next 200 MYa - 2GYa period the increased UV flux will split water vapour in the upper atmosphere into hydroxyl radicals and hydrogen ions—and the latter are sufficiently fast-moving to be lost into space via the solar wind. Over time this will dehydrate the surface and then the upper lithosphere, baking the planet into a cooler, more massive version of Venus. It may take a couple of billion years for the last life forms to die out, but extinction beckons.

However, between the end of the human epoch and the end of a biosphere capable of supporting vertebrate life there stretches a span of time considerably greater than the span separating us today from the first dinosaurs, 241-243 MYa ago.

Continental drift is going to play a role in large-scale evolutionary trends; geologists speculate that between 50 and 200 MYa from now we can expect the Arctic Ocean and Caribbean Sea to close, resulting in a fusion of the Americas and Asia centered around the north pole into a new supercontinent, Amasia. An alternate model proposes the formation of Pangaea Ultima around 250MYa hence. It's very unclear which supercontinent model will prevail, but we do know that roughly every 250-500MYa the Earth's continental plates drift into a single mega-continent configuration, and then subsequently drift apart.

Megacontinents have implications for life because their interiors tend to be arid and often cold—they correlate with large scale glaciation and the interiors are not hospitable. Formation of supercontinents also seems to correlate with large-scale changes in atmospheric oxygen levels. It's also worth noting that the maximum size of vertebrate species increases with the size of the biome accessible to them—the converse effect (island dwarfism) of reduction in size of large animals living in small/constrained areas, such as islands, is clear, and it is noteworthy that the sauropods and titanosaurs (the largest land animals ever) flourished between 240 and 66 MYa ago, originating on the supercontinent Pangaea and continuing as it split into the large continents of Laurasia (which later split into North America and Eurasia) and Gondwana (Africa, Antarctica, South America, Australia, Arabia, and the Indian subcontinent): in other words, huge land masses.

So: 50-200MYa hence, we can expect supercontinents to emerge, and with them, really big land animals. Possibly countering this is the issue of atmospheric partial pressure of oxygen; if it hits 30% (it's currently around 21%) even waterlogged organic tissue will burn, so forest fires resulting from lightning strikes can be expected to devastate surface level ecosystems. (Dinosaurs proliferated in a less oxygenated environment because they had highly efficient lungs, like birds; no surprise there because birds are, in effect, our surviving micro-dinosaurian neighbours.)

But what else is going on ...?

Over the past 200-odd MYa we've seen a couple of arms races driving vertebrate evolution. The first of these was the development of venom; for example, in snakes, venom originated roughly 170MYa ago; tetrodotoxin mutualism (in puffer fish, blue-ringed octopi, and other species) is probably more recent. Many species not routinely thought of as being venomous may indeed poison their prey by biting; for example, the common house cat is well-known for "cat scratch fever" and for bite wounds becoming infected—this may play some role in predation, and I'd speculate that as resistance to toxins emerges over time, so too will more potent venoms be selected for (both by predators, and by edible/prey species that rely on poison to injure or kill predators).

The other arms race is, of course, theory of mind. A predator that can model the behaviour of its prey species is one that can hunt more effectively; and a prey species that can anticipate likely predator strategies is one that can avoid being eaten. We can't know much about dinosaur hunting strategies (and, based on observations of contemporary birds, it would be very unwise to assume that small brains mean low intelligence), but those contemporary species that put lots of metabolic energy into adapting limbs and dentition for killing seem to be less reliant on general intelligence (specialized, saber-toothed big cats have a smaller encephalization quotient than more generalist feline species). Either way, encephalization quotient seems to be slowly increasing over geological time, and we can suppose that predator activities may also be becoming gradually more complex and sophisticated.

So what is the world going to look like in 50MYa?

In the sea, I'm not sure the bony fish are going to recover from what we've done to the ocean food chains any time soon: they may be replaced by cephalopodia (and jellyfish at the invertebrate end). If so, expect some radical new cephalopod forms to show up as they radiate to occupy the niches vacated by the big fish. (Cephalopod plankton filter-feeders like basking sharks? Giant, aggressive fast-swimming squid replacing schools of tuna? Who knows?)

Birds (dinosaurs) and mammals are going to survive and be the main megafauna on land. (Big flightless birds, less so—the need to lay eggs, and the limit on egg size imposed by needing a large surface area to volume ratio for O2/CO2 gas diffusion, puts them at a disadvantage when trying to raise a clutch in an environment full of egg-stealing mammals; it's worth noting that the extinction of the Phorusrhacidae (Terror Birds) in South America coincided with the formation of the Isthmus of Panama and the arrival of mammalian predators.) Supercontinents mean scope for larger apex herbivores, in the extreme scaling up to the size of titanosaurs: a higher atmospheric pO2 may allow mammals to become nearly as large as the larger dinosaurs, although poorer lung performance works against that. But supercontinents also mean poor weather and possible large scale glaciation events.

I'd expect to see more and more species employing venom to hunt their prey, and toxins (often obtained via mutualism/symbiosis from bacteria, like TTX today) to poison their predators: if you see something harmless, fearless, and furry, like a skunk, you should probably avoid eating it if you don't want to die in convulsions.

And we're going to see theory of mind everywhere. Think in terms of bears building fish traps in rivers and pit traps on land. Wolf-analogues coordinating their hunting drives by stationing individuals at high points to relay signals. Raccoons ... shudder.

What am I missing?



Over 50 MY, there's nothing preventing another industrial tool species from developing. It's a really long time: Humans/chimpanzees/bonobos have a common ancestor about 10MYA, so the Earth could reasonably have 2-6 complete cycles in that time.

Think of the arms race in Australia prior to re-pangaeaization. The next sophont could be a kangaroo scion -- they're already bipedal K-strategists, tool use could be right around the corner driven by the highly venomous environment.


Actually, there's no real reason not to have multiple industrial tool using species at once.

After all, they have a much easier source of metals than we did. They can mine our stuff. Energy will be a killer, though. But an agrarian civilization is likely to be accompanied by a mass extinction.


Can I suggest that the immune system will be a big driver here and could take things to some interesting places? In the scenario you describe, the surviving mammals will essentially have the same adaptive immunity that we have (deriving we believe from the first jawed fish, which itself has implications for anything that bites it's prey in the future). That means mammals and birds will be stuck in the same red queen race as currently exists with pathogens. However as Stephen Hedrick wrote a nice paper on in 2004 (open access DOI:10.1016/j.immuni.2004.08.020 ) invertebrates get along quite nicely without our fancy system, and perhaps that lack of red queen race is why they have stayed (largely)the same over a long time. If I understand your question correctly, my point is that the adaptive immune system could be driving the bears etc. to evolve in a way that jellyfish (with their different system) might not. Of course you could turn that on it's head for fictional purposes if jellyfish evolve a pathogen-host repsonse that does drive the evolution of theory of the mind. Especially when you consider just how many viruses there are out there and what they might do on such a long timespan.

One more thing, as I still make this mistake a lot. The surviving creatures in evolution are the lucky ones with the "right" adpations when the environment changes, and then live long enough to reproduce. Creatures don't adapt after the fact. So it is the environment you define that will create the evolutionary outcome you observe.


What am I missing?

I'd suggest, swarming.

The ability for shared genetic inheritance to push for swarmed intelligence and predators. Throw in some real intelligence and you wouldn't want to come up against them on a dark night, no matter your size.


In the 50MYa timescale? Evolution of a new class seems like a serious possibility.

Perhaps a facultative homeotherm, that switches to poiklithermy when the environment is warm enough for obvious metabolic energy savings. Something totally radically and out of left field (just like an early Silurian wouldn't have predicted the evolution of the mammals I'm sure). If humans go, and enough other niches go when agriculture collapses, there will be ecological space for a new class to evolve after all.

If the oxygen content rises enough, how about a gilder-type that, using theory of mind increases, creates forest-fires deliberately and soars on the thermals, then swoops back to pick up cooked meat dinners? A sort of quasi-predatory vulture-type. It creates its own carrion.


"What am I missing?"

Peter Watts' whole back catalog? Honestly, yours is the optimistic version.


>>>What am I missing?

Mutualism between sheep and shepherd dogs allows both to survive. Shepherd dogs guard sheep from other predators, while eating some of them. This eventually extends to other species, resulting in a new species of Pastoral Wolf.


There seems to be a possible block on brain size caused by a lack of available fatty acids that are needed to construct large amounts of neural tissue. Our ancestors got over this by switching from being tree-dwellers to walking savannah dwellers, and by then turning into opportunistic scavenger/gatherers. Our ancestors may also have taken to littoral scavenging, and eating shellfish found on intertidal shorelines at this time; shellfish are easy to get at if you have hands and a propensity to hit things with stones. Chimps have this propensity, but not really the opportunity as they are water-hating forest apes.

So, for an animal to evolve braininess requires an easily-exploitable source of brain-food, together with a good driver for becoming more brainy. Social structures are the most probable driver for animals becoming brainy, with increased predatory efficiency being another one. The early post-dinosaur mammals seemed to embark on a brain arms race between predators and prey which the dinosaurs never really seemed to get started on; most dinosaurs plotted pretty close to the reptile brain to body size ratio and didn't change from the Triassic through to the Cretaceous.

Really, the things that need to exist to force an animal to get smarter are a society in which it lives, where being smarter gives better breeding success, together with a communication system that isn't completely hard-wired and so is susceptible to being altered by greater intelligence.


Naked-mole rats evolved into giant, terrifying naked mole-rats with continent-spawning burrows.

More eusocial mammals for the win!


Eh, it's been done. Chimps for the brains, Gorillas for the muscle. And Charlton Heston for the giggles.


I designed a solar system with a much older sun in an article for Steve Jackson Games a few years back. One of my assumptions about the earthlike planet was that its predator-prey cognitive arms race had gotten to the point where the average predator was mentally somewhere in between a baboon and a bonobo, with the really smart ones approaching human cognitive levels—but without the peculiar invention of language. Since I was envisioning this as a human-colonized world for gaming purposes, I didn't work out the details—but I think this would be a somewhat scary place for those colonists, not so much for the big predators (easy to shoot!) as for the small predators,scavengers, and omnivores. I mean, yes, raccoons are impressive, but how about rats?

The real question seems to me to be whether language is an inevitable outgrowth of high-level theory of mind, or a fortuitous discovery that happens to boost it, or somewhere in between. Will there be a new sapient species to eventually discover traces of the Elder Race?


It's only been 400 Ma since our own ancestors were doing this:

So I'm going to say, 400 Ma from now, distant cephalopod descendants with big hydrogen bladders doing their jet-propulsion shtick in the sky, hybrid aerostat/aerodyne style.


I've enjoyed for some time the idea of an intelligent marsupial race saying, "Obviously placentals can't become intelligent. Look at the problems of getting a big brain out through that narrow pelvic channel! Pouches are a huge advantage in having offspring with big brains."


I have failed in the 50 Ma constraint. I'll go with what as far as I'm concerned is a trope of 'future evolution': bigger, smarter bats.


Well I'd imagine that if the animals are intelligent they will all be real confused by Mt Rushmore.

I'd note this projection lacks consideration of the role and scope of parasites. Maybe it is because I read Parasite Rex not too long ago, but I find the idea that a healthy ecosystem involves a lot of parasites; that they are essentially the drivers of the arms race we call evolution, to be pretty persuasive.

So yeah, needs more examination of microfauna and the role they play


Bacteria that can feed en-masse on our plastic remains thanks to increasing temperatures.

They will either undergo mass extinction after we're gone, or evolve to eat carbo -rich sources....

Such as wood.

Wood might go extinct.


Doesn't "MYa" stand for "Million years ago?"


I gather it depends on the kind of sophont. ^_^ If we're talking Pre-scientific intelligent creatures around Mount Rushmore in the next 3-4 million years they'll probably simply not recognize the faces as anything but shapes on a mountain, either natural or put there by the gods/Giant squiddy monsters/Whatever they use for the explanation for stuff they don't immediately understand.

Of course, if they re-discover Science they'll rapidly realize that there was an earlier species who evolved before being eaten by Giant Cthulhu Monsters.

Also, assuming this happens within 2.4 million years and that something happens which doesn't send a big glacier down to scrub it away. (After 2.4 million years even Mt Rushmore will be long gone)


Doesn't "MYa" stand for "Million years ago?"

That's what I was thinking.

Anyhow I don't have much to add. I think horses will do okay on their own, at least they did in the American West. Raccoons already have thumb analogues, just wait for cats to get theirs (yeah, I know I'm putting that badly). Also picturing island sized jellyfish.

And Mt. Rushmore won't last long without maintenance, at least not on geological time scales.


It seems quite likely that if new tool-using sophonts arise, the timescale in which they will do so will be considerably less than the timescale on which fossil fuel reserves replenish. This means when they hit their industrial revolution, they don't get the unearned inheritance that was a main contributor to the rapid growth of industrial development in our history. It means a MUCH slower industrial revolution, but if they ever do manage to get it off the ground there'll be one interesting difference from our civilization: They will not have had the conditions to develop economic structures that expect year-on-year accelerating growth. Which probably gives them a MUCH greater chance at longevity as a high-tech civilization.

(That's assuming that eventual discovery of nuclear fission doesn't set off a similar accelerating-growth event, just later down the road but to similar effect. In that case, it might be on sapient earthlings 3.0 to have lasting high-tech civilization.)


Like Charlie said ... Raccoons Especially if they get bigger, with bigger brains. Expect a 'coon civilisation real quick - under 1My possibly


On the toxic prey front, I am thinking about food processing. You are a post-bear, and the post-goats are poisonous now. You evolve some gut bacteria to neutralize the poison, but the p-goats get even more poisonous so that isn't enough.

So you evolve to kill a goat, drag it back to your den, rip it open, and puke gut bacteria onto it. Let it marinate for a few days and the nasty poison is all gone. Stinks a lot, but you are used to that.

P-goats develop cleverer tricks, so your detox routine gets more and more complex, and before you know it you are using tools in the process, then fire …

(Red kidney beans are vaguely like this already, they are poisonous until you cook them.)


Several other commenters have pointed this out, but I'm curious as to where you see the other primates landing in this scenario. I know it's overly simplistic to suggest that our closest cousins would simply move into the niche we abandoned, but I can't help but think that they'd be have a head start on everyone else in establishing themselves. Imagine if humans began to emerge in an environment recently abandoned by very human-like creatures, similar minds, similar hands, similar sizes, and so on, and there were tools build for human-like hands lying around everywhere.

Again, I think this is too simple a take, but I feel like you'd need to go out of your way to explain why the apes wouldn't have a leg up.


Long-enough life span, survive childbirth, ability to communicate and form alliances in order to learn from each other and benefit from group communication/cooperation. For now, these are key barriers (what's missing) in cephalopods being able to take over the planet and creating a new global ruling sentience. (Are any cephalopods vegetarian? If they could survive on plant life, they'd have a better chance of taking on other challenges.)

Bacteria design – ability to harness and re-/program microcritters to do a specific job. Ditto grasses. Grasses grow almost everywhere – so the survivors would need to be able to obtain their key nutrients out of grasses.

Worms are also very versatile survivors: live almost everywhere, eat almost everything, many/most are hermaphroditic so reproduction not a concern. Most important – ice worms can survive intense cold, so may be possible to play with that trait to increase temperature tolerance in the other direction.

Because grasses grow everywhere, it should be possible to modify them to eat and reprocess metals, minerals, etc. as required. In turn, it should also be possible to program grasses to pump out edibles. So earliest survivors that have best chance of evolving further should be grass eaters (goats?). The smarter ones - or those geographically isolated from better pastures - might figure out some form of farming or at least that they need to move around from field/eating area to eating area. So theory of mind development is also needed in terms of delayed gratification which means being able to think in terms of 'time'. There's got to be a benefit to the grasses as well - maybe grass seed germination needs a pass-through some type of acid bath (goat gut) in order to get out of its aril coat.

Internalization of beneficial other life form, i.e., something like mitochondria but that performs a similar but different task. Related to this is increasing the brain surface area that is most active in cognition without increasing the rest of the life support system (body) by reducing the size of neurons, axons, etc. and without excessively speeding up metabolism. I'm thinking body- or more importantly brain- cooling (heat dissipation) ability. Or a change in physical configuration, i.e., more convolutions on the brain surface - 'fins to dissipate heat' like in ACs?


That four out of six great ape species are critically endangered may suggest a reason. If we must consider successor primates, I'd suggest looking at baboons. Savanna-dwelling primates, large social groups, numerous...


Several things.

  • I'm not aware of any disease with 100$ kill rate. For one thing, as it goes over 70% (picking a number out of the air), the means of transmission are going to start falling. For another, there are always going to be some segment of the population that will resist it, at least long enough to reproduce, and at that point, evolution kicks in, and 2-3 generations down the line, they'll be immune.
  • Why would the temp keep going up for more than 10 years? And with no fishing, and fewer predators, bony fish might recover in < 50 years.

  • Jumping into the Deciders, sorry, I mean, Evolvers, first, it was just reported about horses, as well as dogs, cats, and porpoises using symbols to convey meaning. Second... some critters have been bred to be smarter (pulling sheep dogs off the top of my head). I'd think they'd be doing more, and possibly using some kind of tools, in under 0.5MY.

  • On the other hand, a LOT of the easiest to extract resources been et by us. Of course, on the third hand, there's a lot of plastic and metal just there for the using.

  • Finally, if we're talking tens of thousands of years, some of those rapidly evolving species may start competing for preserved human information storage - not always digital, but books (CRC Handbook, anyone?). (Hey, says Joe the racconoid, lookit this, Jim Bob: I dug this car out, and broke it open, and it's got a Haynes Manual! We're rich!)

  • Oh, and is this wipeout before or after we have self-actuating AIs?


    Good point, and I can't argue. Although, with the primary reasons for the endangerment of the great apes exiting the stage, they might come back with a, ahem, vengeance.


    Finally, if we're talking tens of thousands of years, some of those rapidly evolving species may start competing for preserved human information storage - not always digital, but books (CRC Handbook, anyone?). (Hey, says Joe the racconoid, lookit this, Jim Bob: I dug this car out, and broke it open, and it's got a Haynes Manual! We're rich!)

    Beat me to it, kinda. More generally, evolution makes use of the tools in place at a given instant, and our post-human evolvers are going to be operating in an environment loaded with human artifacts, at least for a good long while.

    I suspect that "a good long while" may not be sufficient for evolutionary purposes -- things crumble, rust and decay -- but are there things that we'd leave around that would nudge raccoons or whatever in any particular direction?


    The second half of Hot Earth Dreams does actually deal with a bunch of this stuff, although I only went ten million years out. A bunch of what you're predicting is correct for 50,000 years, not 50,000,000 years.

    1) It's always a mistake to assume that the future will look like the past. It's also a mistake to assume that supercontinents produce big dinosaurs. If you look very carefully, you'll see that Pangaea was coming apart by the time the sauropods got really rolling. The better explanation is that they had a set of adaptations (like a set of internal air sacs that would have looked good on a blimp, plus whatever kept their brains from exploding or imploding due to blood pressure when they lowered them to drink and then raised them 20 meters above their hearts to eat) that nothing today has a hope in hell of emulating. Seriously. Back in the Mesozoic, there were Pteranodons that had necks rivaling giraffe necks. Mammals can't do that stuff, nor can birds, so don't expect Brontogoats or Brontopigeons.

    2) Speaking of large, we've gone for small: I suspect one reason we haven't seen mammals get to hadrosaur size is that things like ants, termites, and wood-rotting fungi have gotten really good at taking down rotten wood. Back in the Mesozoic, there's some coprolitic evidence that hadrosaurs ate a lot of rotting wood. They were big enough that their fermenting guts could deal. Nowadays, invertebrates and fungi take that role, but they weren't around then.

    3). In other news: fish won't got extinct. We've been through this before something like five times with previous extinctions.

    4) Coral reef equivalents will certainly be back after 50 million years. It only took them 30 million years to re-evolve after the end Permian mess, and we're not even going that big. My guess is that coral reefs will re-evolve after about 5,000,000 years if we go for a Business As Usual Carbon Excursion. Indeed, I suspect there's an alternation between jellyfish dominated waters when the oceans have a lot of CO2 dissolved and there aren't any reefs, and corals (same phylum) when water chemistry favors reef building, which it generally does. Future reefs won't have many (or any) of the same critters that modern reefs do, but there have been multiple times in Earth's past when all the reefs died, and they've always been replaced by something else. It's a niche that works too well to abandon.

    Note that, if we go extinct this year, I doubt the world will lose all its coral reefs. Things get much worse if civilization doesn't collapse in the next decade.

    5) Oh yeah, island biogeography doesn't scale to continents. That's why the biggest bears are found on Kodiak, not Asia. A continent is a bunch of island-scale habitats linked together. Insular gigantism only works on animals up to around rabbit sized, and above that, they tend to shrink. In the gigantism case, you get size competition favoring the bigger individuals. In the dwarfism case, you get both radically unpredictable seasons (an island specialty), nowhere to go, and limited resources favoring the individuals that live fast, hit adolescence early, and die young. On continents, you get similarly wild weather, but because it's big, there's someplace to migrate too, so you don't have to be a dwarf. Unless you're stuck on a mountain peak, or in a pool, or in any other sort of habitat that mimics an island.

    6) Intelligence gets to be an interesting issue. Yes, many organisms seem to be investing in that horribly expensive brain stuff, which means the rest of their bodies have to be proportionally smaller (that's another nail in the coffin of re-evolving sauropods). I'll gloss over the counter-examples, because increasing brain sounds cool. Does this mean that there will be subsequent "intelligent species?" If, by intelligence, you mean, capable of producing a fire, and cooking rocks until you get civilization again, then it's unlikely, because there's a lot of body mechanics that go into firmaking, not just brains, and most animals don't have the lips or shoulders to pull it off. If you mean the kind of intelligence that elephants, dolphins, bears, raccoons, coyotes, crows, and so forth all display, then yes, I think the Earth will get smarter. But are these animals truly intelligent, or not? That's the sliding scale we always fall off of, because we want the answer to be no, and we're bad at dealing with all the different shades of maybe, let alone all the stuff where they're better than we are.

    Personally, I think you could get just as interesting an answer (what's the Earth like in 50 million years) while leaving humans in, because after 50 million years of coevolving with humans and our stupid cultures, whatever's around could easily survive whatever we throw at them. If you want an example of this, look at Papua New Guinea and scale it to the rest of the world. They're a bunch of smart people, but they're stuck in an alien, hostile environment, and that starkly limits their options. A world where kudzu, mosquitoes, protozoan, fungi, coyotes, and so forth have spent 50 million years dealing with our crap is not a world that we'll rule, although I suspect we'd survive, simply because we're so useful as nutritional substrate and for burning things to create habitat for them. It's also the reason why I think 50 million years in the future with humans is such a nasty scenario. The animals will get smarter on us, since that's one of the ways to deal with us. They'll also get smaller-bodied, which makes them less useful to us as prey items. Except in the cases where being larger bodied makes them invulnerable. And that doesn't even get into what 50 million years of social parasitism will do to our species. If you think cats are bad now, just wait 50,000,000 years.


    A serious question:

    Which is likelier to allow for evolution: a shorter or longer food chain, less or more complexity in the environment?


    If, by intelligence, you mean, capable of producing a fire, and cooking rocks until you get civilization again, then it's unlikely, because there's a lot of body mechanics that go into fire making, not just brains, and most animals don't have the lips or shoulders to pull it off.

    This might go back to the just-posted question, "can they make use of any of our stuff that's still around"? Glass lasts, and we're going to leave behind a lot of lenses.


    Now I am thinking "Evolver" as the title of the far-future novel OGH co-authors in CJ Cherryh's "Foreigner"/Atevi setting.


    Glass and plastic, add sun, and presto! - you've got an oven!


    Plastic doesn't last that long (bacteria are already evolving to metabolize it), while glass gets scratched rather badly. People forget just how tricky it is to get a good glass burning lens to work, let alone to survive 50 million years (and glass fogs up over time--you knew that, of course)

    Besides, you have tried to make fire with a lens, right? It still doesn't get you away from the problem of making tinder and then blowing the coal alight to get the fire going. That latter one is a big problem, as it's not clear how many animals (even, perhaps, Chimpanzees and Bonobos) have the fine breath control to take a tiny ember and blow on it until a flame emerges. This is a testable question, since Kanzi already knows how to start a fire with a lighter, but it remains to be proven.


    Evolution is basically about spaces in the biome, and normally longer food chains and more complexity are regarded as good for that.

    Humans are regarded as bad for evolution of big animals, certainly since the rise of mechanisation but even before that really. We do a lot of monoculture - in quite a lot of countries. Whether that's huge areas of land cultivating rice, massive wheat fields or massive cattle ranches. I don't think many ecologists would argue a huge wheat field is probably the worst of the lot but most people would suggest they're all worse than land not devoted to agriculture - probably including desert (but probably not including salt flats and a few other really specialised land types before someone gets arsey about sweeping generalisations).

    If you look at flora and fauna in the UK for example, which I know is not the world stage, the change to mechanised farming and the loss of hedgerows, copses and the like has wiped out essential habitats for all kinds of plant and animal species.

    But if you want good examples of where evolution is going on hard and fast, take a look at the microflora of any large animal (particularly one that take drugs, so farm animals raised for meat are a good example). Pathogens and commensals keep evolving all the time to out compete each other, evade the immune system, and in the case of meat animals resist the drugs and so on. The more complex the environment, the faster the evolution.


    The answer is yes to all of the above. Evolution is simply about having variation and differential survival.


    Glass can last approx. 1 million years as per site below. Plastics can be remade for forever. It could work.


    Besides, you have tried to make fire with a lens, right?

    Being an old guy, I was once a Boy Scout. So, yes, I have tried and succeeded in making a fire with a lens. (As well as in other ways that did, as you suggest, require more in the way of manipulatory skills and strength.)

    It still doesn't get you away from the problem of making tinder

    s/making/obtaining/ Dry grass and other dry, fine organic material that's found lying around works.

    and then blowing the coal alight to get the fire going.

    I promise you that blowing, while desirable and convenient, isn't necessary. In fact, it being close to solar noon here, I just went out and verified that twice: both times the tinder immediately caught fire (flames, not just coals) without further encouragement.

    Get a lens and some dry grass and try it.


    Done it. I've also done it in suboptimal conditions where all it did was char. The next trick is to get an elephant or a chimpanzee or a raccoon to do it, while also considering how well they'll get tinder.


    cattle and horses are less prepared to go feral if you abruptly remove all human intervention.

    As someone else mentioned horses seemed to have shown they can go feral based on the last 500 years of history in the US. Maybe not those bred for racing but most of the rest should make it.

    Domesticated cattle are another issue. I have trouble with them surviving as, unlike horses, most are about as dumb as a rock. (No insult meant for the rocks of the world.) Plus they can't move very fast for very long. They are a meal waiting to happen for smaller meat eaters such as the larger cats and likely dogs.


    One million years for a 50,000,000 year hiatus basically means that currently glass lenses are out of the picture after 1,000,000 years. As for plastics, "remade" forever doesn't mean it will be useful all that long. Remember that 50,000,000 years ago was the late Eocene, when, just to pick two random factoids, Scotland was about 1 kilometer higher than it is now and had active volcanoes on its eastern edge, while Nevada was a plateau that may have rivaled the present day Himalayas in height and breadth (google Nevadaplano). Personally, I think the Nevadaplano idea is a bit daft, but if a ridiculously high plateau underlain by lava can deflate like a souffle when the subduction zone feeding it lava goes away, then who knows where the Himalayas will be in 50,000,000 years? There might be a Basin and Range province north of India.

    That's the other point. 50,000,000 years is ample time to bury something, like a city or landfill, under most of a kilometer of rock. While I'm sure the atoms of the city or landfill will survive somewhere, it's a good guess that 99.9999% of structured material will be gone. After all, our atoms were almost entirely around 50,000,000 years ago, but the few fossils that survive from that time are basically a rounding error in the elemental cycles, with a side-helping of coal from the swamps. Yes, a few bones survived with cellular structures from the Cretaceous, but almost every atom that was present during that world has been recycled thousands of times since then.

    In other words, saying that some future species will depend on 50,000,000 year-old plastic lenses to make fire and from there, technological culture, is so much silly BS. Still, I know it's fun yanking my chain on this topic, so you can go ahead and be a bunch of yanks, I guess.


    The next trick is to get an elephant or a chimpanzee or a raccoon to do it, while also considering how well they'll get tinder.

    Across millennia and many creatures and lenses, it's hard to say when or if one would, likely totally accidentally, light a fire if it found a usable lens. Or if it did, would follow up, rather than running away in terror. In savanna and similar conditions, I don't think tinder would be a problem.

    Somehow, this strikes me as something corvids might do.


    "Raccoons are impressive, but what about rats?"

    Rats are handicapped by the lack of a good thumb, which raccoons have. Size is one of those things that can evolve rapidly in either direction, but the thumb is a big problem. There are reasons to think that evolving a new thumb is quite difficult. (Consider the Giant Panda.)

    The advantage of rats is rodent teeth, but it's also a disadvantage, and I think that except in specialized environments the advantage lies with the raccoons. If any rodent were to become dominant I'd expect it to be one of the squirrels. Rats seem to only dominate in eco-systems which actually have humans on top. In the wild state squirrels have a strong advantage. They do have the problem of claws instead of nails, but that's probably a simple problem for evolution compared to evolving a new thumb.

    OTOH, if one considers rats more widely, including things like muskrats, etc., then rats begin to show more promise. There are (were?) some fairly large herbivorous rats, probably because the carnivore slots were already well filled. I don't know of any large omnivorous rats...this shouldn't, however, be taken as proof of anything, as my knowledge of paleontology is sparse.


    Bacteria that feed predominantly on plastic have the problem that there's no water present until they build it. I can see surface feeders that use it as a secondary source, and I believe that such already exist, but I can't believe in a species that uses it as the exclusive food source. There are also reasons why wood is difficult to digest that apply as much to bacteria as to anyone else. Notice that cows and termites grind their food finely and mix it well with water before presenting it to the bacteria as food. (I understand that some termites digest the food directly without depending on bacteria or fungi, but they still grind it finely and mix it well with water.)


    I should point out that the article you linked to has some lacunae. For instance, glass-ish things have been around for more like 5000 years (see faience). However, I haven't found a reference to clear glass dating to ca. 100 AD from Alexandria, because you need manganese oxide for that, which means you need a reasonably clean source of manganese oxide. The Minoans were making glass, but it was in the form of opaque beads.

    Yes, the Minoans also had magnifying lenses--made out of rock crystal. Still, before you folk get all worked up about burning glasses, remember that humans had been making fire for hundreds of thousands of years before they got to the point of grinding and polishing quartz to where they could get it to magnify or possibly produce a flame. Indeed, one can ask whether it's possible to produce a burning lens through grinding without already having a fire to produce the precursors needed to grind the lens down, especially in the final stage of getting it clear again. Things like emery powder (powdered corundite) need to be specially mined and transported, for example. You're going to build a mine and a trading network (probably involving things like ocean-going boats) without being capable of producing fire?


    2. Why would the temp keep going up for more than 10 years? And with no fishing, and fewer predators, bony fish might recover in

    The temperature would keep going up because there are lots of slow cycles that have already been pre-filled. But I do think that 4 degrees Centigrade is an overestimate. Probably. Depends on how much methane gets released from melted permafrost.

    One of the big problems that fish currently have is that as the oceans become more acidic, due to the higher CO2 levels dissolved in them, it becomes more difficult to build bones. Most shellfish have this problem even more seriously, and the ones that I know of that use silicon rather than calcium for their skeletons are nearly(?) microscopic. Jellyfish, (most) cephalapods, etc. don't have this problem. While corals are drastically affected, sponges aren't. Etc. OTOH, it does seem to me that the teleost (bony fishes with swim bladders) fishes would eventually recover, those species that survived. Whether they returned to dominance would depend on what had evolved while the acidic oceans kept them suppressed. (It might be that the oceans would AGAIN be recolonized by the fresh water fish. It seems to have happened before.)


    Somewhat off-topic, but the first part of this post reminds me strongly of the plot of The Talos Principle (video game). Humankind foresees its own imminent extinction, and the game is about one of the last great works we manage to finish before we go. I found it rather poignant.


    Also, nobody has mentioned pigs, which quite readily go feral, are social, and sometimes "hunt" in packs. (They're more likely to hunt something that's attacked them, but the pack can forage around the base of the tree the hunter has climbed until hunger and thirst causes the ex-hunter to become the prey.)

    And wild pigs are successful in both forests and arid country.


    If you meant that as a way to get rid of humans and bring in a new ecology in one swell foop, the anime Blue Gender has a similar premise.


    If I understand correctly the Chinese had something called "fire pearls", which it seems to me were probably glass beads, quite a long time before that. Google seems to think this was just a fancy name for pearl, but I don't think so. As usual there's no hint as to how they were made (if they weren't just pearls). One might speculate about lightning strikes, which could account for their traditional association with dragons. (The "pearl" which the dragon chases is clearly the sun, so that's another possible reason for the name.)


    Another group of animals that seems to profit from higher oxygen-levels are insects. During previous periods of high partial O2-pressure (carboniferous) some of them reached enormous sizes. I think that eusocial behaviour (ants, bees..) only evolved much later. So this time around, there might be some space for really huge colonies, especially if the very recent development of mega-colonies proves to be more than a short accident.


    I'm not trying to yank your chain but do feel there's merit in considering other options. So, consider these two items: pyrolysis and sea glass.

    Excerpt: 'Pyrolysis differs from other processes like combustion and hydrolysis in that it usually does not involve reactions with oxygen, water, or any other reagents.[6] In practice, it is not possible to achieve a completely oxygen-free atmosphere. Because some oxygen is present in any pyrolysis system, a small amount of oxidation occurs.'

    So, basically, what you need is heat - it does not have to be 'fire' - therefore sticks, etc. is beside the point/irrelevant.

    Sea glass is a naturally made substance. Probably what gave humans the idea because - I'm guessing - humans probably got/get most of their ideas from nature than from some cognitive abstraction.


    Yep. Wild pigs are such a problem in places like Texas that it's pretty much legal to hunt them year round.

    Of course PETA has a great solution.

    or NOT

    But at the end of the day if people go whoosh I'd bet hogs overrun the US and maybe most of the rest of the planet. At least for a while. They are very smart (dog range of smart), breed very rapidly, and are willing to live most anywhere. And have proven they can exist in the wild without human help.


    Can't find my post re: pyrolysis and sea glass. Anyway, both occur in nature - no fire from rubbed sticks needed - so if higher temps are the norm both might be even more common esp. if volcanoes start sprouting again because of plate tectonics.

    Charlie's comment that theory of mind might be sprouting out everywhere in the far future. So, depending on whether this theory of mind allows for empathy/identifying with the 'other', the deep future UN would have representatives from across 'animal' kingdoms, much as the current UN has Reps from various geopolitical human groups (countries). Considering that humans killed (and in some places still kill) each other but can nevertheless work together for some common causes (disease outbreaks), then - why not! And if the deep future sentients are as bright as all that, then it's also likely that at least some will have become starfarers.

    Also, assuming/given interspecies sentient cooperation.... - technological hurdles would be different and not limited to the physical capabilities or needs of just one species. - cross-species love affairs, gene-sharing/splicing used to help facilitate procreation of such couples. - we won't need to travel to the stars/other galaxies to find novel sentience, aliens.


    It does quite a lot, and your explanation is perfectly correct.

    The nasty part is that a lot of things take up methane and turn it into CO2, including soil bacteria in the Arctic and bacteria all through the ocean. Additionally, the permafrost is known to be up to a kilometer thick in some parts of Siberia, and hundreds of meters thick in parts of Tibet (and who knows how thick in Antarctica). Not all of it will thaw in the 100,000 years or so the heat would last.

    So, to figure out how much methane gets loose in the atmosphere from the Arctic, we've got a hard-to-calculate amount of thaw, plus a hard-to-calculate amount of organic matter locked up in the ice, plus a hard-to-calculate amount of methane locked up in vulnerable clathrates in the Arctic sea floor, minus an unknown amount of methane conversion to CO2 by Arctic soil bacteria, minus a much larger (apparently) methane conversion to CO2 by oceanic bacteria.

    Oh, and did I mention that apparently bacterial activity ramps up as the soil and water warm, although presumably it peaks at some threshold(s) and falls thereafter?

    At this point, I'm agnostic about how much of a problem it will be. It could be huge, it could be minuscule as methane and pretty whatever as CO2. The one thing that is definite is that we need a much better data and models if we're actually interested in figuring out how this might work out.

    If we're NOT interested in working it out, the simple answer is to treat it as CO2 in the long run and go from there. We still don't know the absolute volume, but the problem with the methane is that it makes the peak heat higher before it breaks down into CO2 and gets with the program of long term atmospheric warming.


    Considering venom and theory of mind as the dominant rising traits, I would expect some descendant of parasitic wasps being the top of the food chain before very long.


    Sorry Charlie, but here it's an advantage to be a TV watcher.

    Short term consequences were covered in the series Life After Man, looking at what would happen to structures and environment immediately after humans disappear.

    Long term possible evolution, from near thousands of years in the future to many millions, was covered in the series The Future is Wild. I believe a book came out with the same title. (My favourite are the land squids.)

    An older work is the Dougal Dixon book "After Man" from 1980 or so. Lots of rodent and rabbit descendants on land, including some giant carnivorous forms. IIRC penguins get up to whale size… Highly recommended.


    Is there an upper limit on the sophistication of Cordyceps brain-controlling fungus?

    NB: this is not a question for cat-lovers: there is an upper limit on the sophistication of brain-dwelling protozoans.


    Not sure that poison and toxins will increase over time.

    Using poison to kill your prey seems to work best at smaller scale. Many non-poisonous snakes are bigger than the poisonous. The largest animal I know of that uses a toxic bite as a hunting strategy is the Komodo dragon, and they are smaller and much less widespread than crocodiles.

    Problem seems to be that the predator has to punch through the skin and scales to deliver the venom or toxin, and that's harder than just hamstringing or choking. And while you're waiting for the prey to die, someone else might eat it first.

    As for being poisonous yourself to discourage predators, well it works but again it seems not to scale. I can't think of anything bigger than a skunk. Also skunks are fairly solitary - perhaps being toxic means not only being dangerous to be around for predators, but also for your own kind, so it's difficult to form large social structures?


    I agree, fish might have big issues in the sea, but not all fish live in the ocean, and many are doing ok.

    I really don't think Salmon will go extinct if humans die out tomorrow. Large habit, including both hemispheres. Many farmed, but lots of free roam. Ability to live in both salt and fresh water. The species introduced into the great lakes alone will eventually recolonize the ocean. It helps also they will eat quite a few different things, including the sockeye which feeds off plankton.

    Even with worst case climate issues, Wild Salmon will survive. Maybe they will get pushed North into the Arctic, but currently they can spawn anywhere between Monterrey bay and Nome, giving a massive climate range.

    Interesting enough, with them go bears, as salmon are a good source of calories.


    The only sea glass I know about is discarded glass that gets tumbled with sand and shows up on beaches. Did you mean something else? There's a legend about the accidental discovery of glass on a beach (dudes were cooking on a beach with some unusual rocks, the rocks melted with the sand, and glass was formed), but that's not quite the same thing.

    The key here is that "glass" was around for millennia before people got anything like clear glass, so there's no point in going there. If you want magnification, you need to figure out a way to shape clear quartz, and then to get it clear again. That's an entirely different technical problem, especially getting it polished properly to be clear again once you have the proper shape.


    Chordates have been well covered above. What about evolution in other taxa?

    Arthropods: Arthropods currently constitute something like 80% of all species, so there's already a huge diversity (on the order of 10^7 to 10^8 species). Considered as a phylum, though a substantial number of specialized species will surely go extinct due to global climate change, I'd also expect some interesting new adaptations, e.g., in marine arthropods. Arthropods already dominate some ecosystems, there's already a huge species diversity, so surely insects, myriapods, crustaceans, and chelicerates will do very well. If you want to focus on venom, lots of opportunity among the arthropods, but they have so many useful adaptations that it would be wise to think beyond venom. Finally, from the arthropod point of view, chordate intelligence is highly over-rated -- I mean, look at the primates: intelligent, yes, but also prone to making themselves go extinct; in the long view, intelligence is not a useful adaptation (so say arthropods).

    Echinoderms: Will probably continue to dominate in the ocean depths. In the upper levels of the ocean, ocean acidification and consequences of global climate change will probably cause some species to go extinct, but will probably also lead to ongoing evolution. If we want to speculate about increases in venomous organisms, sea urchins in the intertidal zone and shallow portions of the ocean will be under stress and could continue to evolve more spikes and more venom.

    Cnidarians: If plankton take a really big hit due to ocean acidification, many marine cnidarians could be in trouble (goodbye, Velella velella, sniff). But Cnidarians also have some pretty interesting adaptations: cnidocytes, of course, but also the ability to join together in colony animals (like Velella velella). So we might see relatively rapid evolution in marine cnidarians that could lead in some interesting directions. Hm, what might evolutionary pressure to do hydroid colonies with stinging cells?

    Passing over annelids and mollusks, I'll pause briefly to mention plants. Coastal Redwoods? Doubt they'll survive long (in geological time), they're too specialized. The various algaes? Many of them will do just fine.

    Then there's Archaea: They currently make up (by some estimates) something like 20% of the biomass of the planet. Archaea are everywhere: in the deepest abyss of the ocean, in the Antarctic, in your backyard. And they can apparently transfer genes between individual organisms (according to some authorities, the concept of species does not apply to Archaea). So evolution happens for them in a whole different way. My guess: they are going to do just fine -- no matter what happens to the eukaryotes -- right up to the end.

    In summary: (1) Intelligence is vastly overrated, just ask the arthropods. (2) Being an extremophile that can transfer genes between individual organisms is a successful strategy, just ask the Archaea. (3) Because we humans spend so much time thinking about a tiny minority of types of species (i.e., mammals, birds, and maybe reptiles), we tend to ignore much of the biomass of the planet.


    How about some sea life that photosynthesizes to chlorine instead of oxygen?


    I am utterly baffled at the weebling about glass; it's ecologically irrelevant. It is a natural (if rare) mineral, makes a perfectly good substrate for soil, is biologically almost inert, dissolves slowly in water, and its requirements are renewable resources in a megayear timescale.


    Lenses had nothing to do with the discovery and use of fire. That probably started by maintaining existing, natural fire (lightning, volcano etc.), and moved on to fire drills and fire pistons.


    Yes. I agree with many of the dissenters above. Pretty well all domestic animals and plants will go feral in suitable conditions (sheep do even in the UK), most endangered families (sic) have at least one location they are likely to survive, and a few megayears is enough for a lot of recolonisation. Many of the specialist families will die out, to be sure. It will all be different, and will not yet have recovered the diversity.

    Venom and toxicity is interesting. It is very expensive for the organism to produce, and so tends to be done only when there is enough spare energy; that's probably the reason that highly poisonous plants and large or highly venomous animals are so rare in Boreal regions, but not in the tropics. Thorns and weaponry are cheaper to produce.

    The killer with eusociality and social animals is scale; a species of hill-forming ants can be ecologically stable in a few hundred square miles, but even prairie dogs need a LOT more and as for elephants .... I doubt that arthropods are going anywhere - why should they? - they have adapted to similar changes before.

    Adaptability and inter-generational training definitely work, but I am less convinced about intelligence. The primates in general are not a particularly successful order, what we call intelligence is really a property of the great apes, and they are even less so. In the case of humans (over the 5 megayears of separation from the chimpanzees and bonobos), we have been through several bottlenecks when we came to within a whisker of extinction. Only one of the human lines survived, as distinct from moving into a separate ecological niche.


    "Really, the things that need to exist to force an animal to get smarter are a society in which it lives, where being smarter gives better breeding success, together with a communication system that isn't completely hard-wired and so is susceptible to being altered by greater intelligence."

    Slightly off-topic, but maybe it should give us pause that this exactly expresses the current situation wrt domestic cats - the ones who manage to breed are those who successfully outwit the members of the human host population.


    The next sophont could be a kangaroo scion

    Skippy the Bush Kangaroo


    Why no great apes?

    Perhaps because we've got a disease that is 100% lethal to humans. It's very little stretch for it to be 100% lethal to our close relatives as well


    "It seems quite likely that if new tool-using sophonts arise, the timescale in which they will do so will be considerably less than the timescale on which fossil fuel reserves replenish. This means when they hit their industrial revolution, they don't get the unearned inheritance that was a main contributor to the rapid growth of industrial development in our history."

    Forget the fuel - it's a non-issue. Woodlands regenerate fast, everywhere there is enough water and light, and the UK's industrial revolution happened using (sustainable) charcoal. Seacoal came late. Your point is good, however, but it's the mineral ores that are the problem.


    Oops. Wrong word. 'happened' => 'started'.


    Paging Darren Naish of Tetrapod Zoology, Darren to the Red phone please...


    Lenses had nothing to do with the discovery and use of fire.

    Did anybody say they did?


    It's a standard trolling maneuver here.

    The argument that I and others have advanced is that humans are anatomically adapted to making fire via friction, and that everything from our jaws to our GI tracts and brains have adapted to having fire around.

    The standard, and endlessly debunked, counter, is (to paraphrase sarcastically), "well, oh yeah, some intelligent species will figure out how to use some sort of lens to start fires, and they won't need any other anatomical adaptations to using friction to make fires, so they'll make their own technological civilization based entirely on the lenses we left lying around 50,000,000 years before, or by harvesting the lenses from the freshly dead eyes of whales or elephants, or something that makes this story sound vaguely plausible."

    As noted above, it's mostly intended to wind me up, and it succeeds quite well. Apparently (and I'm being pointlessly judgmental) people who think they're sophisticated hate the idea of Star Trek being somewhat, accidentally right about the utility of high tech aliens having vaguely humanoid shapes, because they evolved from things that made fires for a long time before they made spaceships. But I'm probably wrong about this.

    Of course, I think there rather more interesting issues here, about the nature of intelligence in "animals," about the evolutionary relationships of "intelligence" and technology, and whether there are anatomical as well as intellectual precursors to a species becoming technological. But all these issues get conveniently ignored by weebling on endlessly about glass and lenses. I'm happy to know that I'm not the only one who's annoyed by this.


    Darren Naish is not that helpful on such things, although he is interested in them. Regardless, if you kick some money to him over at the tetzoo podcast's Cash For Questions, he will spend some time trying to answer it (that's at


    Actually, intelligence isn't necessary for social parasitism, which is what cats do with us.

    The point of social parasitism, if we're talking about, say, ants and the caterpillars that they care for as if they were ant larvae, is that the parasites have cracked the "social code" of their hosts and are cared for as offspring. If you're starting to be creeped out by people who treat their pets as their "kids," you;re correct: that's what social parasites of ants do to their hosts.

    The nasty part of social parasitism isn't that the parasites trick their hosts, as is claimed. Instead, and this is critical, the hosts actively select the social parasites that best elicit parental care for them. Presumably, the ants get as much from caring for social parasites as we do from caring for our pets. Social parasitism is about the hosts selecting the most attractive parasites, not about the parasites tricking their hosts into adopting them.

    In other words, we hosts enjoy tricking ourselves into treating pets as kids. By doing so, we help them evolve to parasitize us. We're actively helping populations of cats, dogs, rabbits, gerbils, pythons, koi, pigeon, marijuana, and so forth evolve to become social parasites on humans. It's only been going on for a short time, so speciation hasn't happened yet. If civilization fails, the social parasites that manage to survive will probably be under strong selection to resume their former, independent lifestyles. We call this going feral, but it's just another form of natural selection.

    With ants, some of these social parasites have been around for millions of years, and they no longer live independently of their ant hosts. It's unfortunate that OGH's scenario involves humans going extinct, because the world would be so much more interesting if humans lasted 50,000,000 years and had a really huge menagerie of true social parasites whose wild relatives were long extinct.


    Ma - million years ago (time difference) My - million years (duration)


    You've missed out the big reset potential of another rock the size of Mount Everest dropping out of the sky. The last one killed all the big animals and meant a whole bunch of niches were available to the wherever got there first.

    And that would be a small thing compared to the effects of the impact of a Mantle Plume on the scale of the Deccan or the Siberian Traps which are capable of embuggering the climate for millions of years and poisoning the oceans with sulfur. There's plenty of evidence that the late Maastrichtian was not a nice place to live with the oceans becoming increasingly impoverished, a huge decline in planktonic diversity towards types evolved for high-stress environments, abrupt climate swings and the disappearance of dinosaurs from parts of the planet long before the Chixculub nightmare turned Mexico extra crispy.

    So I don't think the mammals will necessarily make it through the next planetary redecoration.


    The UK's Industrial Revolution got going because there was a lack of charcoal. Despite intensive coppicing of forests, there simply wasn't enough wood in Britain to meet increasing demand for iron. Coal was unsuited to smelting iron because of its sulfur and phosphorus content, but Abraham Darby learned that Birmingham brewers had been using sulfur-free coked coal for malting barley, so he gave it a whirl and three centuries later we're reaping a climatic nightmare.


    firemaking is not at all hard and gets easier if the oxygen content goes up

    Even without the right respiratory stuff, bellows are not hard to make

    My guess is the key requite is good manipulators (thumbs of their equivalent) and not much more then that

    i think lenses are a bit bar fetched though

    To answer Charlie's original question, the most likely scenario is on of the smarter runnner-up species (raccoons, chimps etc) goes intelligent fast and then dominates the ecosystem. You don't need fancy civ to do that dominating, you just need fire and basic tool use (archery, buildings, light agriculturist) and social apparatus that allows cooperation

    Which species wins will depend a lot on which is initially best adapted for the new ecological conditions


    The other aspect is that none of those people seem to be gardeners! Any of us know how fast glass turns milky in soil - it's slower in some soils and fresh water, but a lens will become unusable in a couple of centuries at most. Nor do they have a clue how hard lenses are to make.


    Er, no. It was the move to the cities and the increase in steelmaking (i.e. the progress of the industrial revolution) that demanded more fuel. I accept that I was referring to an earlier date for the start of the industrial revolution than is used by most people, but the changes in technologies really started in the 17th century. The point here is that charcoal is inadequate only with a very high demand density; while that is the way our industrial revolution went, it is NOT the only possible one.


    Fuel - 50 million years appears to be enough time to lay down some new layers of tar, coal, gas, etc. I don't understand why the other minerals wouldn't last though if we're also assuming massive tectonics that would churn up mineral supplies/deposits. What quantities of which minerals would probably depend on how deep, hot and energetic the tectonics get.

    Limb evolution à la aquatic mammals: sea, land, sea. So, existing evidence that species can evolve to, from and back again in very different environments. And because almost every largish creature has a similar body plan already (bilateral symmetry, head-tail, paired fore and aft limbs, etc.), I really don't see such a big deal about one or several species hitting it lucky and evolving appendages that are sufficiently 'hand-like' to better manipulate their environments. What's more critical is the ability to foresee the need to manipulate the environment.

    Strictly amateur gardener and have never buried any glass so don't know that the glass would be destroyed; all the glass that I do keep outdoors and above ground though remains clear - not scratched up. Not the timescale Charlie's looking at but my understanding is that the stained and clear glass in the old European cathedrals is holding up quite well too. At some point the concept of 'maintaining one's tools/resources' ought to kick in if the so-called tool-using species is going to survive whatever their immediate here-and-now is in the deep future.


    I have a fairly extensive project dealing with future evolution, so I may be able to offer a few cents. In my project, I have humans cause a mass extinction event that wipes out 60% of life on Earth, but many species do manage to survive. Homo sapiens die out 2.5MYH (million years hence) as the biosphere heals and organisms evolve to be mostly useless or too conniving for humans to effectively consume with a good population. Instead, humans begin specializing into certain cultural routes, to the point where various groups begin to diverge into separate species. These human species manage to survive for a while, but geological, biological, and climatological shifts slowly pick off each human species till there are none left by 12 MYH. Following that, life continues to evolve, going in various direction with too many side stories for me to dwell into.

    But in respect to future intelligences, I have 3 (to be four) intelligent species evolve between now and 100MYH-but only one has a good enough bauplan to develop a highly developed technological civilization. The first one is a sapient dolphin that evolves 11MYH (assuming modern-day dolphins are not as intelligent as us, which may be a mistake) and least 23 MYH, going extinct when Antarctica begins to permanently thaw. The next species is a sapient predatory parrot descendant the size of a golden eagle that evolves 28 million year hence, that's limited in it's technological development due to it's small size.

    The final sapient evolves 100 million years hence from a not-yet-existing clade of endothermic squamates, and they actually develop civilization, manage to piece together from paleontological evidence that there was a sophont-caused extinction event beforehand (us), and figure out how to avoid doing the same catastrophe. But then I have a flood basalt screw it all up and completely wipe them out.


    Without something similar to the carboniferous era, which is unlikely, only a little coal and oil will form. Most mineral ores are the result of biological action, of types that are unlikely to recur. The minerals will be there, only in much less accessible forms.


    It's a standard trolling maneuver here.

    As noted above, it's mostly intended to wind me up, and it succeeds quite well.

    Well, that you've gotten wound up is evident. But why do you get so wound up over, of all things, the thought that a post-human species' evolution might be influenced by our left-behind artifacts? Lenses or whatever. Evolution operates on many time scales, and even stuff that lasts, in a few cases, some tens or hundreds of thousands of years might be relevant given the right circumstances.

    But it really isn't all about you, and I doubt many craft their posts with the intention of trolling Heteromeles. Perhaps a bit of time off and tending the garden is in order.


    There's two things going on here:

    One is that there's a lot of Paleogene coal--it's what powers Wyoming. Thing is, there's also a lot of rather low-grade coal. A lot of the really good stuff was deposited in the Carboniferous. Coal varies wildly in quality, so saying "we'll get all our coal back in 50 million years" is incorrect, although some coal formation is almost inevitable. It's simply the remnants of buried marshes and swamps, and in a hotter climate, there will be more of these.

    Similarly, we'll get some oil back in 50 million years. The North Sea oil is about that old, IIRC. The thing to remember is that oil can be favored by things like deep sea or near-shore anoxia (so that dead material sits on the bottom without getting consumed by anything but slow anaerobic bacteria), and a lot of sediment coming in from rivers, which we'll also have, due to fewer dams and increased erosion from bigger storms. Hothouse Earth conditions (which we'll get into with a severely changed climate) seem to favor the formation of oil.

    Let these dead algae get buried to the magic depth where the carbs break down to oil, but not so far that they fry, let the rock above them be impermeable so that they get trapped, rather than percolating away, and you've got an oil dome, at least so far as I understand it.

    Note that, while oil will form, getting it trapped and concentrated into a form where it's worth drilling for is a far more uncommon phenomenon. Apparently there's for more oilish junk in rocks than there is useful petroleum, just as there's a lot of coal that's so intermixed with sand and gravel that it's not worth burning.


    I agree that the fixation on lenses on here is kind of daft, but I also think much the same about the idea that a fire-using species has to start by rubbing two Boy Scouts together and so must have a near-humanoid anatomy before fire becomes an option. This isn't to wind you up, it's simply that I see nothing to support the contention that only one method of initiating fire can be postulated.

    Learning how to breed fire from an existing natural source of ignition (lightning, volcanism, spontaneously-combusting rotting material or whatever), and keep it going, is a comparatively straightforward matter, requiring "only" an appropriate degree of intelligence plus the basic ability to pick something up without slobbering all over it (so bright cats OK, bright dogs not so much). Given those attributes, plain undirected curiosity will do the trick.

    Learning how to create a source of ignition, however, is a different matter entirely, requiring complicated directed activity and the intelligence to perform the direction; you have to do a lot of apparently pointless things, which are hard work and which don't of themselves give any indication of giving any useful result, before anything happens, and it seems to me it must surely require at least some informal understanding of physics and some idea of what you're trying to do before you start. It's not easy to learn even when you already have the brains and the hands and people to show you how to do it, nor is it easy to do - certainly the friction methods aren't, their widespread use being more a matter of widespread availability of suitable materials than anything else; and people still relied a great deal on such practices as never letting a fire go completely out, and carrying a firepot of smouldering embers around with them to start new fires with, right up until they got matches.

    So making use of fire is something that can begin much earlier in the development of a species's intelligence than being able to light one at will can. (And if it is true that cooking was necessary to allow humans to develop larger brains, it must have begun much earlier.)

    This would mean that humanoid anatomy is not necessary for developing techniques of ignition. A species will begin by breeding fire when it reaches some minimum enabling level of intelligence, then much later, when its intelligence has increased further, will come up with some method of starting a fire from scratch according to what its anatomy lets it do. So a bird, for instance, probably wouldn't bother with friction, but instead go for banging stones on rocks and working out what kinds of stones give the best sparks.


    For me, the fun question are: how much are humans evolved around fire (both making it and needing it), how much does this adaptation (which long precedes our species) make it possible for us to create a technological civilization, and finally, if you believe that an intelligent species needs to be able to make fire long before it gets around to making a technological civilization, how much do structural adaptations to making fire constrain what an alien technological species might look like?

    This is the Star Trek aspect: if you believe that producing fire requires a vaguely human-like form (somewhat human-like shoulders, somewhat human-like hands, and something like a human-like mouth to blow an ember into a flame, and something in the neighborhood of human size for muscle and weight), then it follows that technological aliens should be somewhat human-like, and that ideas of "starfish aliens" are rather bogus. How could an intelligent starfish (or an intelligent cockroach, or an intelligent parrot, or an intelligent fish, or an intelligent raccoon) produce fire?

    Some around here reject that idea, because they want starfish aliens. Their normal retort is that their starfish aliens will find some other means of fire, inevitably involving sparks or lenses, and try to use this to invalidate the whole idea. There are rather more clever retorts, but for some reason, sparks and lenses get repeated far more often, even though, as others point out repeatedly, those are extremely improbable at best.

    The bigger, nastier question is about the nature of intelligence. I'm perfectly happy with the idea of an intelligent alien starfish. What I'm not happy with is the idea that the only way an alien starfish can be intelligent is by building a starship and piloting its way into a SF story. In other words, in the face of all evidence, we conflate technology with intelligence.

    Yes, there could be intelligent descendants of raccoons in 50 million years. However, if they're making fire, let alone building sophisticated tools and technologies, my bet is that they're going to be bipedal, about human-sized, and about as similar in behavior and appearance to modern raccoons as we are to lemurs.

    Ultimately, standard definitions of "intelligence" are quite biased and based on the idea that it's something that makes humans different and special. This has been a pattern for over a century. Whenever animals demonstrate a skill (like tool-making or speech) that was previously thought to be a hallmark of human intelligence, the definition of intelligence changes so that such skills are excluded. Frans de Waals published a book on this topic this year (Are We Smart Enough to Know How Smart Animals Are?) and it's well worth reading.

    So far, the only uniquely human trait that animals haven't demonstrated is the ability to make fire by friction, and that's why we really need to focus on fire and how humans are adapted to it if we want to understand why we're doing technology and everything else is not.

    So no, I'm not going to take some time to go out and garden. I'd suggest instead that you might want to do some reading.


    Here's a scenario to think about:

    Some graduate student splices a myelin gene into an octopus, and then when humanity vanishes, the lab animals escape to the ocean.

    For those who don't follow these things, the early nerve researchers used octopi and squid, because those creatures have nerves with a diameter of a millimetre or more. Why so big ? Because the increased size gave increased speed, which they needed because only vertebrates have the nifty myelin sheathing.

    Captive octopi get bored, so they have the right brain architecture to make use of smaller faster nerves. And since they evolved some intelligence, the selection forces would presumably exist to select for even more intelligence. And they don't need to evolve thumbs, thank you. What tool would they develop first?


    Re: 'because they want starfish aliens'

    It's space-faring lobsters or nothing!


    Vernor Vinge had this a minor aside in Marooned in Realtime. Millions of years in the future, one of the hi-tech survivors is studying a vulture analog that starts forest fires so it can eat the resulting carrion.

    It builds a pile of rocks and tinder, and then tosses rocks at it while flapping wings to fan it.


    'What tool would they develop first?'

    Toss up between lever and Allen key (continuous action/varying angles). Can't see it being a hammer (abrupt/fast force).


    Actually, that's not the problem I'd solve for octopi, if I were attempting to take over the world.

    They're pretty good at using found tools already. I suspect that smelting iron would be beyond them, but that's not their big problem.

    So far as I know, the key problem for all the cephalopods is that they die after reproduction. They're semelparous, just like wheat. I know this goes for the squids, octopi, and cuttlefish that people have studied, although I don't know if it's true for all the deep sea species or for the two species of nautilus.

    The reason they don't teach their young is that the father dies after insemination and the mother dies around the time the eggs hatch. Every cephalopod enters the world a larva and learns to be entirely on its own.

    So if you want to play Trickster and give the 'pods a chance to be on top, you need to mess with whatever aspect of their biology has forced them into Big Bang reproduction, and allow them to be around to teach their kids. The ones that don't eat their kids (ahem!) may well take over the undersea world once they figure out how to have a multigenerational cultural, and everyone will blame you.


    Well, that's an interesting one...

    My answer rambles a bit, because I need to lay out a bit of a background. Skip to the end for the creepy and disturbing bit.

    There's a facile answer, in that splitting chlorine using UV is far less favourable, in terms of energy,than splitting water and harvesting energy from the freed proton while discarding the freed oxygen.

    So it seems obvious that any organism doing such an inefficient thing as splitting chlorine out of dissolved sodium chloride (and somehow managing the incredibly damaging intermediate products) would be out-competed by the oxygenic photosynthesisers.

    So the facile answer is: "ain't gonna happen".

    However, there's a missing fact: almost all photosynthesisers on our planet are laughably inefficient - in particular, one of the downstream components of the process, the Rubisco enzyme, is a perfect example of evolution finding 'false maxima' in the landscape of possible solutions and getting stuck there - and we're talking orders of magnitude below the theoretucally-achievable efficiency, so there is actually space for a different photosynthetic process, even a less-efficient one in theory, which might in practice be competitive and displace the planet's oxygenators.

    The problem, of course, is "You can't get there from here": there's no obvious progression from existing biology to such a novel and complex system,and you have to displace an existing and ecosystem of competitors for limited resources.

    But this was equally true of oxygenic photosynthesis! And we know for a fact that the serendipitous subcomponents and mutations did, eventually, all happen at the same time in the same organism...

    Any argument against Chlorinating photosynthesis arising has to pass the test of "That's true about oxygenating photosynthesis, too!".

    True to some degree, at least.

    Now for the creepy bit.

    Some microbes use sunlight to oxidize arsenite to arsenate. It's kinda niche, because arsenite isn't found everywhere, but it's a thing that living organisms actually do in a few places.

    Some archaea photolyse water with UV and send the proton down a completely different chain, in a reaction that binds CO2 without releasing oxygen.

    So alternatives to oxygenic photosynthesis can and do arise, and two of them are known to exist today.

    Personally, I see chlorogenic photosynthesis as highly improbable - there are so many obstacles to it ever happening - but oxygenic photosynthesis is kinda tricky, too, and a 'restart from zero' scenario for life on Earth might just end up with chlorine-breathing scholars declaring oxygen-based ecosystems to br impossible...

    ...Oh, and using Oxygen to gas their enemies in their equivalent of WW1.


    This was intended as a reply to this comment from Dick Bruere about Chlorine-releasing photosynthesis arising; but it doesn't seem to have 'threaded'. Apologies for any confusion


    Funny thing about Nature, seems there's always an exception cropping up. Wonder if this species is finding current weather/climate to their liking.


    'Additionally, unlike other octopus species in which females tend to die after producing a single clutch of eggs, female larger Pacific striped octopuses can lay many clutches of eggs continuously over the course of their adult lives. While in captive environments, females laid eggs for up to six months and brooded for up to eight months. Even after their eggs began hatching, females continued to feed, mate, and lay hundreds more eggs--demonstrating yet another unusual behavior that the team believes is exclusive to this species.

    Over this same two-year period, Ross displayed several combinations of male and female octopuses together in a shared exhibit at the Academy's Steinhart Aquarium to observe social interaction and group dynamics. He found that both sexes were able to peacefully cohabitate, at times sharing the same den and supporting earlier observations by Rodaniche that reported groups of up to 40 individuals living together in tropical Eastern Pacific waters. While on exhibit, several pairs mated daily and produced multiple clutches of eggs, giving the team the opportunity to observe habits of brooding females as well. These cohabitation behaviors have rarely been observed among other octopuses.'

    Journal Reference:

    Caldwell RL, Ross R, Rodaniche A, Huffard CL. Behavior and Body Patterns of the Larger Pacific Striped Octopus. PLoS ONE, 2015 DOI: 10.1371/journal.pone.0134152

    "the only uniquely human trait that animals haven't demonstrated is the ability to make fire by friction"

    The words "by friction" are redundant; they haven't done it by any other method either. Reason being that none of them have even got to the stage of using fire yet (and generally tend to be afraid of it anyway), so the question of making it hasn't arisen.

    My objection is nothing to do with a desire for starfish aliens, but simply that the assertion that any species developing the ability to make fire has to do so by friction has nothing to support it.

    Other methods of making fire may be unlikely candidates for development, but so is friction. It's only being suggested because people have been told that it works (even though their personal experience is probably that it doesn't). If you are a primitive sapient without the benefit of any such external knowledge, the chain of steps necessary to achieve it is not much less obscure and unlikely than the chain involved in the lens-making case, and there is equally little reason to embark on any of them.


    Not quite true. Kanzi the Bonobo is perfectly capable of making a campfire and cooking some food over it, so long as he has a lighter: (among others).

    I don't have any influence, but I'd love to get a survivalist in to see if (s)he could teach Kanzi how to use a hand drill and spin up his own fire. That would invalidate a lot of what I'm saying here. My guess is that even though bonobos are a lot stronger than humans, their hands are not very well adapted to keeping a hand drill spinning, and they may have some trouble manipulating an ember onto tinder and blowing it alight.

    The other thing is that there are a bunch of friction methods that humans use, including drills, plows, and saws. There are also fire pistons, which works on the diesel effect, but still require a lot of the same coordination issues. Each works best with a particular set of materials, and hand drills seem to be the most widespread. The particular problem is that all of them require fast, powerful, two-handed (often with a foot as well), and precise manipulation of the apparatus. That particular combination of requirements actually keeps most of the species on our planet from creating a fire the way we do. Lots of species have precise manipulation, even more have power, but power and precision are a rare combination.


    Since I have kids and read children books a lot I think mostly about fluffy animals. Badgers occasionally share dens with foxes (and if wikipedia is teo believed very occasionaly with rabbits!), from looking at documentaries a lot of encounters between middling predators or omnivores is more threat display and careful attempts at 'hunting' the other than anything really dangerous to either. So, taking the trend of more theory of mind, we have see overlapping 'guilds' of species that are mostly not dangerous to one another (eggs/puppies etc. are always in danger of course) and communicate (threat display!). Now ad theory of mind, and you maybe have post-bears coordinating with post-badgers against - post-sheep - pity the ps have their pastoral wolf bodyguards.

    The poison reminded me of a thought I had a while back: The Gruffalo. In the story, it's treated like the big bad apex predator, but actually ... If you look at the build, the poisonous wart and the prickels on the back are clearly defensive weaponry. I know of no predator with defensive weaponry. Also the gruffalo is bigger than the fox or owl or snake, but not by that much. I think the gruffolo is more like a bipedal boar, often on it's knobbly knees digging in the dirt for ubers and small rodents (indeed, it's favorite food is mice on bread).

    Also, might any aquatic mammals make their way back onto land, as furry snakes?


    Heteromeles wrote: This is the Star Trek aspect: if you believe that producing fire requires a vaguely human-like form (somewhat human-like shoulders, somewhat human-like hands, and something like a human-like mouth to blow an ember into a flame, and something in the neighborhood of human size for muscle and weight), then it follows that technological aliens should be somewhat human-like, and that ideas of "starfish aliens" are rather bogus.

    It seems to me that current scientific thinking in this subject has moved on a bit from the "must look like a human" argument. You can see the change in articles about "dinosaurids", intelligent descendents of the velociraptors. (Yeah yeah velociraptor is not the proper name, but I haven't had enough coffee to try and spell dromo-whatever just now.)

    When Russell and Seguin first speculated about a dinosauroid in 1982 (Google for troodon sapiens) they made it very human like, standing upright with a short neck and no tail. More recent speculations (Google for darren naish dinosauroid) look more like the original animals, arguing that a larger brain and manipulative hands could work just fine without standing upright.

    However, Simon Conway Morris is still around to argue that intelligent species must look like humans…


    The bigger, nastier question is about the nature of intelligence. I'm perfectly happy with the idea of an intelligent alien starfish. What I'm not happy with is the idea that the only way an alien starfish can be intelligent is by building a starship and piloting its way into a SF story. In other words, in the face of all evidence, we conflate technology with intelligence.

    Moving on to your bigger question, here I think most of the evidence we have is that increased intelligence does imply technology.

    Among mammals and birds, there's a lot of improvised tool use. The mammals with the highest EQ are the great apes, and they're the ones that make heaviest use of tools. (See the bonobo with a lighter example from above.) There seems to be a strong correlation between tool use, complex intra-species communication, and complex social structure.

    (It's possible that, say, mountain sheep are all philosophers with a rich internal mental life that we know nothing about, but I rather doubt it.)

    But dolphins and orca have communication and social structure but no tools. That's why I wrote "most of".

    So while I think it's likely that intelligent species will eventually build starships, it's not automatic. And this has been more or less mainstream science fiction for at least forty years. Larry Niven was writing about intelligent but non-tool using dolphines and Grogs around 1970. I'm sure other writers have done the same.


    Yay nature! I'm so glad that some octopi buck the trend. I guess giving them myelin would be better thing too.


    I just finished rereading Cherryh's 40,000 in Gehenna. It's a great example of a set of species that are and aren't...well, that's the point of the story, actually. I'm not going to spoil the fun if you haven't read it.

    Anyway, I'm quite happy with intelligent species that never build starships, since we have yet to demonstrate that starships are buildable or that we can build them. Assuming we can build starships, it's also fun to contemplate the full spectrum of traits that pass for intelligence in humans, and contemplate how many different non-starfaring species could have some part of them, and what it would be like to land on their worlds.

    Oh, I forgot. Just like there are some octopi that reproduce more than once, there are dolphins that use tools. Yay nature!


    Getting back to the original question, there's some potential weirdness. After all, it's only 56 million years from the end of the Cretaceous to now, so if we went extinct, that's the equivalent of going from rats and pigeons to Miocene mammals.

    One other thing to realize is that nature went from a weird little hooved otter thingie to fully pelagic whales in about 10-12 million years. Rapid evolution is extremely possible.

    In other words, 50 million years is permission to make the world look like just about anything: there will probably be mammals, birds, reptiles, fish, cnidarians, echinoderms, beetles, wasps, ants, and probably most of the others. How big they are, what's in charge, even whether it's an ice age or not--that's all up in the air, although I'd suggest a reasonably high probability of Earth being in a hothouse climate, not as an icehouse as it is at present.


    the chain of steps necessary to achieve it is not much less obscure and unlikely than the chain involved in the lens-making case

    If one looks way up-thread, the lens stuff started as an instance of "what effect on the evolution of post-humans might all of the stuff we'd leave behind have?"

    I.e., if the raccoons/crows/whatever were to find lenses in our leavings and perhaps discover their fire-starting properties, would that have an effect? Nothing whatsoever about making the lenses, just finding them.


    Rapid evolution is extremely possible.

    Yes indeed. "Punctuated equilibrium" and all that. The event postulated by OGH is a pretty big punctuation point, and the possibility of really rapid adaptation/ evolution should be considered. Just how rapid rapid might be is worth considering -- I suspect it might be in the hundreds of generations in some circumstances.


    Rapid evolution is extremely possible.


    But perhaps going back to the OP, I think 50 megayears is way bigger than the scale of adaptation, evolution and change for all the stuff that will happen between 1 January 2017 and then. And the multiple changes between now and then will create their own environments in which subsequent changes will happen. IOW, it's going to be a system characterized by extremely nonlinear feedback, quintessentially chaotic, so who knows what 50,000,2017 CE is going to look like?


    50 million years is permission to make the world look like just about anything

    Yes, this. It's not shortly after one reset event; it's long after, with time for many cycles of overlapping development. Entire families of creatures will have shown up, become widespread, and gone extinct.

    It's effectively a whole new planet, so if you feel the urge you can pick a favorite biological order and make up a future for it. Trying for a coherent overview is hard.


    Yay nature! I'm so glad that some octopi buck the trend. I guess giving them myelin would be better thing too.

    I'd guess that a smart octopus would start by developing a stabbing knife (as opposed to an edged knife). They'd ambush predators that came within striking range. A spear would be a later improvement. Blood in the water would attract scavengers, who hopefully didn't prefer octopus. A symbiotic relationship could grow, where some scavenger protected octopi in return.


    To clarify the time scales a bit:

    If we went for a full-on, business as usual blow all the fossil fuels into about a 1.5 teratonne discharge of CO2 and equivalents, the climate would spike hard, settle back down to about 5oC warmer, then return to modern temperatures over 100,000-400,000 years. This is the Hot Earth Dreams scenario, and I'm now leaning more towards 100,000 years for return to present. It's not clear what methane does to this, as noted above, because figuring out how much methane makes it into the air is really hard at this point in time.

    If there's a full-on mass extinction, it's thought will take 10,000,000 years, 30,000,000 if it's as bad as the end-Permian disaster, for biodiversity to return to where it was 10,000 years ago. In that time, it will take 5,000,000 years (10,000,000 for a P-T event) for coral reefs to show up again.

    And we're looking 50,000,000 years out.

    Now, if we're talking about humans going extinct in a couple of months, we probably won't have a huge mass extinction, unless we really don't understand what's going on with methane release. Climate will return to 20th Century normal in a few centuries. Basically, almost every concrete and metal structure we've made will be non-existent in 10,000 years. At that time, the remaining evidence of humanity will be a pile of rocks where the great pyramids sit, some toxic waste dumps turning the water interesting colors here and there, some radioactive crap for any alien passing by with a radiation detector, and a bunch of eroded bulldozer features in places where the wind hasn't erased them, like the mountain-tops removed in Appalachia. We won't have had time to drain all the groundwater, so there will still be springs.

    In other words, it's basically a Life After People episode. Lions and elephants recover, swim the Suez, and reinvade Europe in a few decades. That sort of thing. Fifty million years after that could bring just about anything. Termites farming elephants for their dung, perhaps. Who knows?

    The key point is to pay attention to all those zeroes, because there's a big difference between 100, 10,000, 10,000,000, and 50,000,000 years.


    Maybe a disease could be a minor annoyance to one species but have a 100 percent kill rate to another. Like if dogs suffered from some minor flu like disease every year, but humans were suddenly susceptible to the same disease and it killed them. Dogs are distributed throughout human society, so the disease would survive in them without killing them, but humans would catch it, pass it to hundreds of other humans, and then die. Of course humans would just get rid of dogs, or stay away from them. Or a disease could be engineered, in which case all bets are off. If you could design it to be contagious for a year before turning fatal that would do it.


    If groundwater extraction were to stop now then what sort of timescales are required for aquifer replenishment?


    Anything from weeks to (effectively) never. There are aquifers that filled when the climate was wetter than today, and will not refill until and unless it changes back again.


    Not quite. We don't know whether we have triggered a change in the climate that would continue even if we stop forcing it; there are authorities that argue both viewpoints. It would assuredly return to a more normal state, but it might be fairly unlike the 20th century. Other than that, I agree.


    Thought that might be the case.


    I thought 'MYa' and 'GYa' would specifically be a million/billion years ago too?

    In my experience, the common two-letter abbreviation for 'year' is usually 'yr', and the SI abbreviation is 'a' (I assume for annum)

    Wikipedia source:


    Thanks for that. My excuse is that I'm a 'merican "Gen Xer" and weren't taught that pesky International stuff. Not entirely true, and I meant to look it up myself but forgot.


    Not something you missed, but rather a quibble about several assumption. First, as Heteromeles noted, you can see complete biosphere replacements and reboots within periods of 5 to 10 Ma. (Note to punters: Ma BP is used for “before present” = years ago; Ma is just a duration.) With a 50 Ma duration, you’re likely to see at least one complete biosphere replacement, and more likely a couple. Predicting the results of that genetic shuffling? You’d have better luck predicting tomorrow’s lottery numbers. For proof, have a look at some of the creatures from the “Cambrian explosion” and ask yourself whether you could have predicted the inhabitants of a modern pet shop based on the Cambrian critters.

    Second, on the kind of time scale you’re discussing, it doesn’t much matter whether you posit a 100% lethal virus that spreads faster than the flu, or just let global warming take its inevitable nasty course. In both cases, humanity will be gone in the blink of an eye on such long time scales. Of course, no disease is 100% lethal, but even a relatively low (e.g., 75%) mortality rate may damage civilization enough that humans won’t survive in most parts of the world; combine with ongoing climate change and we might not survive anywhere. In fact, even without such an event, it’s not clear we have the legs to last another million years as a species. Fast forward 50 Ma and I don’t expect us or our descendents to still be here. On the flip side, we’re so close to the technological tipping point that we may well be able to do the singularity thing, or at least modify our genome enough to survive otherwise lethal conditions. But Charlie ruled that out as part of the starting conditions.

    Charlie: “Megacontinents have implications for life because their interiors tend to be arid and often cold—they correlate with large scale glaciation and the interiors are not hospitable.”

    True, but life is tough, and you find significant amounts of life even in seemingly hostile environments. Consider the Qinghai-Tibetan Plateau, for instance. Even hyperarid places like the deserts of northern China (incorrectly called the Gobi Desert) have surprising amounts of life. The wildcard, of course, is how much surface water will be left after some of the changes that are coming.

    Charlie: “the maximum size of vertebrate species increases with the size of the biome accessible to them... we can expect supercontinents to emerge, and with them, really big land animals”

    True, but that’s the maximum. There are many other constraints that prevent animals from reaching that maximum, and given current climate change trends and your likely supercontinents, I would expect the opposite trend: smaller animals that use resources more efficiently, not larger ones. The thermodynamics make more sense in a resource-constrainted environment.

    Charlie: “Possibly countering this is the issue of atmospheric partial pressure of oxygen; if it hits 30% (it's currently around 21%) even waterlogged organic tissue will burn, so forest fires resulting from lightning strikes can be expected to devastate surface level ecosystems.”

    Seems unlikely. Yes, the severity of fires will increase, but not beyond levels that are manageable to most ecosystems. (For example, boreal forests have long since evolved to survive a fire cycle that would eradicate most southern forests. Alternatively, severe fires may produce ecosystems with limited fuel continuity, thus less catastrophic fires.) And I’m leery about the actual impact of the “anything will burn” hypothesis. As prima facie evidence, I offer the Carboniferous, when oxygen levels hit an estimated 32.5% or even higher. And yet, here we are, back at ca. 21%. I suspect that really high oxygen levels are a self-correcting problem, mostly because oxygen is so damned reactive. Everything that can burn under those conditions will eventually burn (i.e., combine with oxygen, thereby removing that oxygen from the atmosphere) until oxygen levels drop once more to non-combustible levels. The one planetary system we know well has tended to evolve towards equilibrium, and to have enormous buffering capacity. That’s not to say the equilibrium couldn’t end up as nasty as that of Venus, with only extremophiles surviving... but the Venus scenario seems implausible to me.

    I don’t buy the venom evolution idea at all. Off the top of my head, I can’t think of any system where a venomous animal is the keystone species, or even a truly dominant species. (Spiders being a possible exception within the very limited context of the insect portion of the food web.) Were this a likely evolutionary mechanism, most of the world would resemble the cliché vision of Australia -- or Harry Harrison’s Deathworld. To support the hypothesis of a venom arms race, you’d need to propose a plausible selection pressure in which venom is favored far beyond the level to which it has been favored in documented evolution. And that seems unlikely. There aren’t any venomous predators that hunt large game (e.g., deer, antelope, elephants), but given the magnitude of the food resource implied by large herbivores, any mutation in favor of venom production from (say) cats* would clearly have enormous selection benefits and we’d see many more large venomous creatures both now and in the fossil record. Or at least a couple conspicuous exceptions. The fact that we don’t see such evidence is not proof your idea is impossible, but it is pretty good evidence it’s unlikely.

    • Cats really aren’t even remotely venomous within the context of your venom arms race hypothesis; the toxicity of cat bites is far too low to confer any evolutionary advantage. (Also note that human mouths are just about as nasty, and people have died from seemingly innocuous dog nips. Komodo dragons are the extreme case of nonvenomous but highly toxic mouths.)

    You’re probably right about the extinction of bony fish, but it’s likely to occur sooner rather than later. The rapid and ongoing death of key reefs (including the Great Barrier Reef) will destroy their associated ecosystems, including the scary proportion of the oceanic food web that relies on reefs for their reproduction. Reefs may move to colder waters, but that's not guaranteed to happen fast enough to prevent a collapse; they will eventually re-evolve, but not quickly. Heteromeles’ estimates of 5 to 10 Ma seem reasonable.

    In the much shorter term, I agree that cephalopods could be our successors if the right chain of coincidences occur: they’re already remarkably intelligent, have remarkable manipulative appendages, and if the main genius niche is vacated by us, they’re a credible successor taxon. After all, they’ve been around at least as long as we have as a branch on the tree of life. (However, the fact that they haven’t become an undersea civilization of supergeniuses over that long period is a strike against them. And see above for whether they’d survive 2 or more biosphere reboots and still be here in 50 Ma.) Your suggestion of a cephalopod-dominated near-future (ca. 1 ka) ocean is plausible, quite apart from the whole Cthulhu thing, but perhaps not that they'd survive multiple reboots. I suspect that the biggest problem is that they’re predators up near the top of the food web, and if the food web takes a critical hit, they will too. It’s not clear to me whether higher life forms can out-evolve a rapid extinction event such as the collapse of a food web; I don't think there are any herbivorous or omnivorous octopi or squid. But cephalopods or equivalents will probably re-evolve in 50 Ma.

    Jellyfish are an interesting Plan B, since they’re more likely to survive things that would wipe out higher life forms, including cephalopods. My understanding is that they’re not very nutritious, so most things won’t eat them. Ditto for algae, which is where we probably started the evolutionary sequence leading to our modern biosphere. But I suspect the jellyfish will be extinguished by the plants. For example, certain red algae may be the only exception to the venom arms race notion on an ecosystem scale, though green algae achieve similar effects by consuming all the oxygen and thereby excluding other species. Not venom, but the same result. So you might see a plant-based reboot of the biosphere more than a reboot by any animals.


    Since these octopi tolerate (or even invite) each other's touch, then at some point while holding tentacles they're likely to capture some yummy prey. This prey catching occurs a few times by accident until one octopus makes a cause-effect connection and persuades a couple of buddies to try it on purpose. Success is intermittent until a further realization - that the more tentacles they hold outstretched together, the higher the chances of capturing prey. At some point other family octopi attach themselves and help grow this hunting net and successfully bagging ever larger prey in their area. They've become a successful living, growing hunting 'networks'. After some time a few other octopi add some refinements in net design, area hunted and prey hunted.

    Many generations later an aging yet nimble octopus thinks: 'Fine, we're catching larger prey and everyone is able to eat so much that we don't need to hunt as often. In fact, we can't eat all of the prey at once so there's nuisance creatures starting to moving into our area, fouling our habitat so that after we wake up after each feeding, we have to move into less familiar, so more dangerous, waters.'

    Even with this realization, this moving hunt goes on for many generations as the octopus family grows and adds yet another generation of octopi to their hunting net. Over time though the prey/fish caught are all getting smaller (younger). Even so, these smaller prey fish were so numerous that every octopus in the hunting party was able to eat their fill and there would still be some young fish left over. Indeed after such a hunt and a few hours after gorging itself that one octopus coming out of her post-feeding torpor noticed a small fish bumping into her tentacles that were dangling over a small rock shelf, covering/barring an underwater cave entrance. Still too torpid, the octopus decided she didn't care enough to move her tentacles, so fell back asleep leaving the fish bumping into her tentacles. A couple of days later, when another octopus came over for a friendly two-tentacle wrestle and the two octopi pals started feeling peckish, the host octopus (and primary gate-keeper) recalled the fish in the cave, stuck a tentacle into the cave and grabbed an afternoon snack to share.


    you are missing the larger point on the fire making thing, H

    A bow drill is a tool for concentrating force to produce friction

    Any species with enough brains to really nail simple tools could get to fire eventually

    Being strong'ish and having good manipulators is more the path to tools then the path to fire

    Best evidence is homo sapiens ancestors cultivated fire for a long time but it wasn't until homo sapien sapien rolled around that they got good at tools that they also got good at making fire


    A couple more things.

    As you noted, there's not a good correlation between maximum body size and maximum continent size. The easy way to remember it is that Kodiak Bears, the largest brown bears, live on a very small island near Asia, and there aren't any Asian brown bears in the same size range.

    If anyone wants a more concrete example, Pangaea reached its largest extent between 300 and 175 million years ago (Permian and Triassic) and the largest dinosaur known (Argentinosaurus huinculensis) lived on the island continent of South America in the mid-late Cretaceous, 97-94 mya). This is why I keep stressing that people have to pay attention to numbers. 97,000,000 is a long time after 175,000,000. Furthermore, there's a 125,000,000 year stretch of Pangaea (the Permian and Triassic) which didn't support many giants. The giant sauropods didn't get rocking until afterwards, during the Jurassic, when the continents were splitting up.

    2). We'll probably never see a repeat of the Carboniferous, with that huge production of oxygen due to the burial of undecayed wood. The reason is that there are a lot more wood rotting organisms around now than there were then. Wood-rotting fungi and termites both evolved during the Mesozoic, while the Carboniferous was before the Permian in the Paleozoic. In other words, I wouldn't worry about huge amounts of oxygen in the atmosphere for awhile, if ever.

    3) The general trends apparent in evolution at the moment seem to be: --eusociality (insects, mole rats, shrimp, etc.) --venom production (venomous snakes are mostly post-KPg developments, in parallel with the explosion of mammals. Similarly, bees and ants have taken off since the dinosaurs disappeared). --Increasing complexity of symbioses between plants, fungi, bacteria, and animals (mycorrhizae, pollination, nodulated nitrogen fixation, etc.). Symbioses have been around since life began, but the kind of interactions brought by flowering plants, ascomycete and basidiomycete fungi, and hymenopteran insects are still complexifying.
    --Compound flowers in plants (not just in the daisy family, but in many other plant clades) --diversification in a number of animal groups: rodents, bats, passerine birds, perciform fishes, beetles, parasitic wasps, etc. These are probably the ancestral groups of tomorrow. Note that none of these groups require crazy symbioses to survive as a group (although most have members that indulge), so this is actually counter to the previous trend.

    Still, the sad part of all this is the lack of humans. This exercise is sort of like positing that people never figured out how to make a really hot fire, and so the iron age never took off. You can do a tremendous amount with bronze, but the widespread smelting of iron changed everything rather radically. A world without humans may cough out another technological species in the fullness of time, but a world with humans adds a couple of additional layers of crazy. We take all the symbiotic trends and turn them up to 11 since we're the most relationship-crazy species on the planet. We make all sorts of novel materials and habitats with our unique predilection for fire, and we have economists who make boom-bust cycles seem rational. Organisms from marijuana to ebola are all furiously evolving to take advantage of us in some way or other, and we've done more to mingle the planet's biota than anything since continental drift and the ice ages. Why play with a simple Earth when you can have drama?


    There may already be birds who use fire, although not to cook prey but rather to drive it out of hiding.

    The evidence is anecdotal at this point, but it's a fascinating prospect.


    Bears discover fire, for one thing.


    I find it hard to imagine any human artifact to play a big role for the coming evolution, should we be gone in a few months as per the OP. As others pointed out, on the timescales we are talking about everything is rubble before a rodent grew a new whisker or something. Our visible tgraces will be the extinctions andthe species we have bread and spread around the world.

    If I understand this correctly, it would be wrong to assume one 'climax' biome for every location that nature will invariably drift to. Instead, animals, especially large herbivores, can terraform by keeping forests from growing and maintaining grass dominated steppe landscapes. So if there's no more humanity on new years eve, it is conceivable that the pendulum will swing towards the steppe side of the balance in many places that have been forested in human memory. And maybe this will be or legacy, that we bred and spread terraformers all over the world and that these will reset big parts of the world to steppe. I tend to think that this will matter down the road, but will it?


    The evidence for fire use goes back to Homo erectus, and part of it is anatomical. The thing is that many animals use tools, including some invertebrates.* The thing about getting fire through friction is that you need a lot of friction in a small space, which requires strength, weight, and precision. A parrot or raven may be precise enough, but it isn't strong enough or heavy enough to get the wood very hot. An elephant is easily heavy and strong enough, but its trunk isn't built for the kind of precise, repetitive motion required to generate friction. Indeed, most primitive ignition methods require two hands and often a foot, so animals that only use a beak or a trunk are doubly disadvantaged.

    It's not even clear (to me at least) whether apes can do it, simply because they don't have the kind of power grip that hominids have. Fortunately, this can be tested.

    Then there's the issue of blowing a coal alight. That takes extremely fine breath control, and a lot of animals simply don't have it. If you've ever watched a dog or cat try to talk, you'll see that they don't have the coordination with their lips and diaphragm to make a consistent sound, let alone blow a little stream of air sufficient to blow a coal alight without blowing it out. I suspect it's something that goes along with speech, and I'm not sure how many animals have that kind of control of their mouth or breathing. Again, this can be tested experimentally, if you can figure out how to teach animals to do it.

    The upshot is that humans are unique because we've got this combination of traits that, initially and fortuitously, allowed us to start lighting fires.


    "So you might see a plant-based reboot of the biosphere more than a reboot by any animals."

    The only organisms I recall which require the presence of fire as part of their life cycle are certain trees whose seeds won't germinate until after exposure to high temperature, giving them an advantage of unobstructed sunlight and growth medium free of competitors after a forest fire. In a world with oxygen levels low enough, or moisture high enough that fires from lightning are partly inhibited, selection pressure might favor a plant oozing globules of clear resin to focus sunlight on dry tinder, acting as a burning lens. Then similar to how photsensitive cells in lower animals evolve into eyes by way of an infolding surface to produce a pinhole camera effect and eventually a clear membrane over the cavity becoming a lens for sharper focus, a plant could gradually produce resin globules in more efficicient lens shapes that move like sunflowers to track the light source, focusing on piles of tinder the plant also generates in nearby woody receptacles. Definitely wouldn't want one sprouting by your house.


    There s not compelling evidence that I have seen for pre home sapiens doing anything other then cultivating fire, the general theories seem to be that sapiens were the first to master the art of making fire

    While it's true animals use tools in the stick-into-anthill sense, the things that sapiens do around making tools are a world different.

    Fire making apparatus are just a sub set of comply manufactured tools. While it's true that a lot of animals are not going to have the manipulators or strength to turn the raw materials of their environment into tools (wood, stone, animal products ) bring able to do so is a pre requisite to actually getting survival value out of all that extra brain tissue

    Animals that don't have that combo are likely to never evolve intelligence, intelligence is biologically expensive and probably not worth the cost if all it does is predator / prey simulation

    Also you don't need to blow on the coal in fire by friction, that step is optional. I myself have made fire with a bow, in Boy Scouts , you don't need to blow on it you can just feed it tinder and it will still work, the blowing makes it easier is all

    You could also use an animal bladder or stomache to serve as a bellows if you needed to


    The upshot is that humans are unique because we've got this combination of traits that, initially and fortuitously, allowed us to start lighting fires.

    But as Vernor Vinge readers know, fifty megayears is enough time to evolve grenade beetles. grin Chimps, elephants, and crows are smart enough to figure out how to use them usefully. Cats...might set them off for the fun of it. Cats can be assholes.


    Let me back off a bit and ask a bigger picture question. Are we looking for a successor species at fifty megayears or just tossing out biology fantasies? Octopi, sure; we've covered that before. There are already plenty of medium sized mammals with reasonably dexterous paws. Birds are smarter than we're comfortable with.

    Take your pick for the class; at 5E7 years we'll see entire new orders arise, though it's very likely Earth will still have critters recognizably similar to present day rodents and soricomorpha (shrew-like creatures, formerly Insectvora before a reorganization). Bats seem to be doing surprisingly well, competing with birds in the big-flying-critter arena. Coincidentally, these three orders are only a little over fifty megayears old, if I'm reading Wikipedia correctly.

    This is far enough in the future that it will take a sophisticated species to even detect that humanity once existed. Do we want to assume some species like ours, human style minds in a different housing? Honestly, I think it's more fun to assume the Earth does not get a single tool using verbal species that dominates the surrounding wildlife. Without a single destabilizing creature overrunning the planet the overall biological diversity can be examined for itself rather than in relation to that one apex species.


    "Giant, aggressive fast-swimming squid replacing schools of tuna?"

    So basically slightly larger Humboldt squid, who are already big, fast, and aggressive.

    "Humboldt squid are carnivorous marine invertebrates that move in shoals of up to 1,200 individuals. They swim at speeds up to 24 km/h (15 mph; 13 kn) propelled by water ejected through a hyponome (siphon) and by two triangular fins. Their tentacles bear 100-200 suckers, each lined with razor-sharp teeth, with which they grasp prey and drag it towards a large, sharp beak." - Wikipedia


    I'd expect offshoots of another species to develop industrial civilization within 10MY and derail any further predictions. My top candidates are crows, parrots, hornbills, apes again, or the mimic octopus. That list is chosen entirely on a fuzzy idea of those animals seeming smart from what I've heard: I'm not an evolutionary biologist, I just hang out with them.

    This is predicated on the assumption that intelligence is significantly more common now than it was in the past. That seems fairly safe - crows use tools, most birds don't. If it evolved earlier, they'd all do it (or most at least).

    I also assume there's some intelligence threshold where tiny improvements in intelligence or dexterity outweigh all other mutations and evolution piles those on. Until the species is advancing at the rate of civilization: then evolution is so slow that it's irrelevant. (This is also why you wouldn't expect two civilized species to evolve at once: the timescales of evolution and civilization are too different.)

    However, it's possible that there's more to an intelligence explosion than just tipping a threshold. Humans are evolved from an apex predator with a weird niche. Maybe the reason all the big brain mutations stuck was because our ancestors were already overkill and could get however much food they wanted, so evolution wasn't balancing the calorie needs of large brains. If that's a requirement, it would take a lot longer for intelligence to happen again.

    134: would take a lot longer for intelligence to happen again.

    That's an open question. We've got no idea how common our combination of verbal skills and dexterous manipulators might be. It's happened exactly once in Earth's history and it's not immediately obvious how likely it is to happen at all. We can look at the near misses in the animal kingdom today but it's much harder to even guess how common they were tens of millions of years ago. We can say the chimps are close but we got there first, or the octopi are dexterous but too short lived, or crows are clever but too small - but many of those things don't clearly show in the fossil record. Do you know anything about the smartest animal behavior in the paleogene? I don't. I doubt anyone does. Maybe there were some really clever rodents that we've not found yet; a raccoon type creature could evolve, poke at things with sticks, and go extinct without leaving an obvious mark. If merely clever animals are common in deep time, that doesn't imply good odds for a successor species rising up on its own after we're gone.


    No, stone tools are also pre-Homo, slightly. However, this is distorted because the only things that have survived are stone tools and the evidence of fire. Elaine Morgan and others (me included) have provided evidence that the most plausible first tools were baskets and perhaps nets (which need rope), combined with water-based food gathering. But that's heresy to the savanna fanatics, so you won't find much published ....

    Scott Sanford has it right. The great apes are a recent development; only genus Homo has been very successful, and is quite likely to be self-destroying. Heteromeles list #123(3) mentions more successful ones, but I am not convinced that those are ongoing changes - we haven't anything like precise enough evidence to know, and I pointed out that the use of venom outside the tropics is rare and limited. My betting is on something we don't expect :-)

    What few people have mentioned is how fungi are evolving (except Heteromeles with lignin), probably because we simply don't know; the record is sparse. We can forget the stupid ideas that some authors have perpetrated - fungi long ago specialised in biochemical wizardry and using resources that other organisms can't. But what about a lichen-like ant or shrimp that could eat most plants? That would turn the ecosphere on its head in short order, more thoughly than even climate change will!


    Elaine Morgan and others (me included) have provided evidence that the most plausible first tools were baskets and perhaps nets (which need rope)

    Interesting! Would you have any references for these or should I just try to google for them?



    like sunflowers to track the light source, focusing on piles of tinder the plant also generates in nearby woody receptacles. Definitely wouldn't want one sprouting by your house.

    No indeed:

    (True, the Niven version uses mirrors rather than lenses, but still...)


    I had some, but that was decades ago - and my computer has 35 GB of old mail, mostly in the form of text messages! Google for the aquatic ape theory, and ignore her first books - she was prepared to learn from constructive criticism. There is a lot of lunacy that goes under that name, and remember that the savanna fanatics often misrepresent and malign their opponents; the variant that fits with my knowledge is adaptation to swampy areas and small watercourses (*). I am happy to post my personal information, which is all checkable, but it would be a bit long and I will do it only with permission. I am happy for a moderator to send you my Email address, if you want to ask directly - please prod after a month if I forget to respond.

    [[ Done - mod ]]

    (*) Interesting. Upon looking at the references, it seems that at least one professional anthropologist has come to the same conclusion as me, for very similar reasons (surprise, surprise). However, he addresses only the bipedalism issue.


    Recommended reading: "Survivor" by Richard Fortey ISBN for pbk: 978-0-00-720987-3 Pub. Harper/Collins 2011

    He examines, as the title suggests, species that have well-survived (as well as a few that didn't. Horseshoe Crab, Velvet Worm, Stromatolites, Extremophiles (In Yellowstone, specifically ), Lingula worm & others,Huperzia & Weltwischia, Lungfish/Hagfish/Lamprey,Platypus/Echidna/Tarsier, Ferreret frog ( Mallorca ) & some Pleistocene remnants & extinctions - Musk Ox/Mammoth, of & Cockroaches.


    Since I first saw you express it here I have wondered how widespread this speculation about fire and the humanoid shape is, though I suppose the context for it isn't all that widespread anyway. You're right that obsessing with possible counterexamples misses the point, and there are interesting questions that doing so sidelines. I'd like to raise such questions, but first I wanted to share the thought chain the idea prompted this time around.

    Every year I watch sulphur-crested cockatoos eating passion-fruit. They use one claw to grasp on to whatever is the perch of convenience, they hold the passion-fruit high in the other claw and use the hook on the ends of their beaks to breach the fruit. Once the hole is large enough they lick out the contents. I've seen two cockatoos share a fruit in this manner. And noisy squabbly riots over dropped passion-fruit on my carport roof.

    The force between upraised claw and beak must be modestly significant. I just now visualised a series of cartoonlike drawings of a sulphur-crested cockatoo. Gathering the materials, making a shaft, bending the bow and tying the string. Grasping the shaft in both claws, one raised and drawing the bow back and forth with its beak. Fanning the tinder with its wings. And now you have too.

    I can't see this working for either tying the string or looping it around the shaft. And you're probably right about the need for weight. But anyhow - cockatoos have a similar lifespan to humans, appear to pass information through generations, sometimes use tools.

    The interesting question to me is about the connection between tool making, language and whether (one of) our idea(s) of intelligence is really a way to model the world around us in a way that allows us to make new things in our heads before we make them with our hands. This is a different animal to theory of mind. Sure the social capabilities from language are a huge advantage, but plenty of social species don't have anything like abstraction (as far as we know... linguists seem to change the definition of language whenever some non-human animal demonstrates a capability previously thought unique to humans) and still manage their social world. I wonder how fire fits in with that. And also whether changing the world is really the mark of intelligence, whether we could have species that do all the social stuff and eventually develop a complex enough inner life that the absence of fire makes no difference.

    But that's maybe when someone asks about lenses again.


    Ma - million years ago (time difference) My - million years (duration)

    There's a push in some quarters to redefine "Ma" to mean "megaannus" = "million years" in the duration sense, as part of trying to define an SI "year" under the rubric annus.

    "Myr" is also used for "million years (duration)", and is more common than "My" in astronomy, for what that's worth.


    Google for the aquatic ape theory, and ignore her first books - she was prepared to learn from constructive criticism.

    Thanks, I will google for it! Sorry for not googling first - I was at work at the time, so, easier to write a short post here than really do anything.

    I'm familiar with Elaine Morgan, and I think I have to read her more recent books. I have the Finnish translation of The Scars of Evolution, I bought it over twenty years ago, but I think that's one of her first books.

    So, google and aquatic ape theory it is. I have seen much of the criticism on the Internet and I'm not sure I agree with most of it.


    Since we're dealing with a very large time span, maybe we should likewise expand our viewpoint and consider what's likely to happen at a comparably very large volume/area, i.e., solar system, galaxy, etc.

    There are some very slow changes that over time might make a difference: - The Earth is slowly moving away from the sun, as is the moon from the Earth. - Both the sun's and the Earth's diameters are increasing resulting in slower rotations. - Earth's axial tilt is increasing but is expected to wobble back. - Earth's orbit is becoming a bit more eccentric so greater variability in solar irradiation.

    There's more here:

    And then there are the once-in-a-million-year events that can signify catastrophic changes: asteroid strikes, larger planetary neighbors gaining or losing a moon, large planetary neighbors being hit by asteroids, etc. (If we ever lost Jupiter or Neptune, surviving a rain of asteroids might be iffy.) Basically unpredictable and 'game-over'.

    Bottom line: The exact same sequence in animal kingdom evolution might not be possible because the larger environment itself will be changing.


    A world without humans may cough out another technological species in the fullness of time, but a world with humans adds a couple of additional layers of crazy.

    There are two reasons for ignoring humans, at least for the sake of this speculation.

    The first is that "imagine humans survive (on Earth) into the future" is pretty bog-standard science fiction: not really anything new or unique, except perhaps the arbitrary 50 Myr endpoint.

    The second is that it can be more interesting to work within some plausible constraints. If you include humans, then you have to include the effects of cultural and technological evolution, which in turn depends partly on advances in scientific knowledge, which, as Karl Popper pointed out some time back, is fundamentally unpredictable. So there are few if any constraints on what might happen.

    It's plausible to speculate about the end of raising animals for food within the next few hundred years, due to some combination of technological development, changes in morality, and desires for more efficiency in food production. It's also possible that keeping pets could go out of fashion in the next few hundred or thousand years. In either case, speculation about the evolution of "social parasitism" by pigs or cats in the distant future becomes moot.

    (Or you can imagine a future where the "Hedonistic Imperative" has been implemented has been implemented, and predation is no longer allowed.)

    A world where kudzu, mosquitoes, protozoan, fungi, coyotes, and so forth have spent 50 million years dealing with our crap is not a world that we'll rule

    In order for that to be plausible, you have to implicitly assume that we never get any better at science and technology than we are now, and also that we never decide to wipe out the species in question (or do so accidentally). The problem with evolution is that it can only work on generational timescales (relatively fast for protozoa, etc., slower for coyotes). Cultural evolution -- and scientific/technological evolution as a part of that -- keeps getting faster, and in the long run will get out ahead of biological evolution in areas where it already isn't.


    Is there any evidence that human (H.sapiens sapiens) grade intelligence is likely to re-evolve? It's only happened once in the ±500My that metazoa have been around to evolve it. Also, Fermi's paradox. With all due respect to Simon Conway Morris and friends, isn't it more likely that this was a freak event?

    But that aside, I think you can probably also discount other hominids picking up the baton, because, honestly, any Mcguffin that can take out the whole of humanity from Mexico City to North Sentinel Island will likely take out closely related species as well, especially when they're already critically endangered. I'm inclined to rule out cephalopods, because even species which guard their eggs ignore their larvae, and I suspect a degree of parental care is necessary to the reproduction of culture beyond a certain level. So on the 50My timescale I reckon the best bet is birds, presumably parrots or crows- why not both? You can argue that some troodonts were probably as bright as crows, and the theropod line doesn't seem to get beyond that level in all the time it's had to do it, but different times, different selective pressures. As relatively small animals, several species could achieve sentience in small isolated environments, and we could have a lot of fun with first encounters without ever leaving Earth.

    My real fantasy is the emergence of eusocial intelligences in which the individual members of the hive are not fully sentient, but collectively they can reinvent calculus on a wet Saturday afternoon.


    %deity alone knows. And SFreader's points are good, too. My guess is that the evolution of 'our' sort of intelligence depends on an environment in which (a) a primate-like manipulative and communicative animal arises, (b) a stable enough state that a LCA/chimp-like variant becomes fairly common and (c) whatever conditions were needed to encourage that in the direction of intelligence. I.e. I don't think that it would arise anywhere with a very different geoecological history from ours. As far as other kinds of intelligence goes, I know my limits ....


    - The Earth is slowly moving away from the sun, as is the moon from the Earth.

    The Earth is moving away from the Sun very slowly. Over 50 Myr, this will amount to a change of less than 1000 km, which is much smaller than the annual variation in our distance to the Sun.

    - Both the sun's and the Earth's diameters are increasing resulting in slower rotations.

    Um, what?

    (The Earth's rotation is slowing because of tidal effects from the Moon. The Sun's rotation is slowing primarily because of the solar wind and its connection to the solar magnetic field.)

    - Earth's orbit is becoming a bit more eccentric so greater variability in solar irradiation.

    Known variation in the Earth's orbital eccentricity happens on timescales of about 100,000 years, which is irrelevant to Charlie's 50 Myr scenario.


    You won't find my observations there - they were pers. comm. - I don't know if she published using them, but I doubt it. The paper I linked includes about a third of my analysis.


    The last bit of my comment: "... will get out ahead of biological evolution in areas where it already isn't." should read: "... will get out ahead of biological evolution in areas where it isn't already."


    Yes - I also did these numbers. Even so, it appears that even such small changes might matter as per below.


    'Proceed with caution

    And this is where the study has encountered scepticism. “The key part of this paper is the temperature reconstruction, which is really valuable,” says Eelco Rohling, a palaeoclimatologist at the Australian National University in Canberra. But he adds that the question of how the planet will respond to atmospheric CO2 over the long term requires more detailed analysis.

    In particular, the study fails to account for subtle changes in Earth’s orbit that affected global temperatures and helped to drive the expansion and retreat of glaciers throughout the time period covered by the analysis, says Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies in New York City. He says the effects of such orbital variations must be considered when comparing the glacial era to the present.'


    Yes but, as OGH says, the solar constant, day and month will be slightly different. SFreader's point that we shouldn't think parochially is good - what about novae and supernovae? And we don't really have a clue how common extra-system junk passes through, except 'not very often' - I am not talking about massive effects, but quite a small gas cloud could have a bit impact on our ecosphere, especially if it contained a lot of methane or other interesting compounds.

    One more thing, as I still make this mistake a lot. The surviving creatures in evolution are the lucky ones with the "right" adaptions when the environment changes, and then live long enough to reproduce. Creatures don't adapt after the fact. So it is the environment you define that will create the evolutionary outcome you observe.

    I'm glad someone made this point, because I think we should at least consider the validity of Gould's description of evolutionary history here when considering these projections, which teases apart evolutionary diversity from evolutionary disparity. Species today are certainly more diverse, and specialised, than they were in the distant past, but we don't have so many distinct biological archetypes as we did back in the Ediacaran era.

    Partly I think this is important to consider when thinking of how a sapient species might arise. We now know that humans didn't evolve in the strictly linear manner which is depicted in the "Evolution of Man" imagery, but that there were a multitude of hominid species, sometimes existing side-by-side, which would crowd such a picture.

    In this sense not only are we mixtures of homo sapiens sapiens, Neanderthals, Denisovans, and at least one other sub-species, but we also have that there were hominids which co-existed with our ancestors that were not so much our missing links as dead-end branch-offs. Point being that if we're going to get sentient racoons, we'd first expect to see a host of sentient/pseudo-sentient racoon species and sub-species first emerge: an 'ecosystem of sentience' from which the mixed-species survivors will emerge.

    The other reason I think the Gouldian logic is important to consider, though, is to imagine the counter-example. When was the last time something weirdly different to everything else emerged? Something like grass, or tree-symbiotic fungus? In terms of general trends, it seems likely that future evolution will trend towards more diversity and less disparity, but what if, against probability, we get a disparate new phylum which somewhat upends things? I hesitate to think what, because I'm not sure if I can come up with anything plausible. But perhaps a set of species which appear to imitate the jelly but are able to spread onto land and demonstrate very non-jelly characteristics, including forming variously unfamiliar symbiotic/predatory/parasitic relationships with existing species.


    Fire seems to be a thing that we keep coming back to, yet I'm not the only person who's done hearing about lenses. Let's try something else. What if the fire users aren't corvids or octopi but eusocial insects? Ants and termites have been cultivating symbiotic relationships with other species for many millions of years and that gives them a wide range of chemical tools. Posit the development of a hypergolic substance and its use as a defense is obvious; once it exists at all it can be easily turned to other purposes.

    We know what medium sized mammals do with fire: we cook food and make metals. What might social insects do?

    They could use fire to control plants and animals in their environment. Some might start forest fires, hiding underground while the flames passed, and emerging to feast on the leftover biomass. This is only an occasional way to get food but opens the way to developing a fire based land management strategy; fire using insects could co-evolve with entire ecosystems based on periodic burns. This is still done by humans so we have a demonstration proof that it works.

    James Nicoll once related that small explosives are nuisances to large anthills, doing dramatic damage that's repaired in a matter of days. Insect-on-insect bombing may not catch on. On the other hand, they might lead to features large enough to scare off or injure large insectivores; this could make attacking social insect hives even less attractive than it is now.

    Perhaps there's a role for fire in making heat-treated building materials, or for heat driven air conditioning within nests (note that some termites already have this technology). In temperate regions even a small heat source might get a colony through the winter.

    There are a few ideas I came up with in the night. Does anyone spot something fun I overlooked?

    • ObSF: The Hephaestus Plague by Thomas Page (1973), featuring a species of beetles which rub their back legs together as crickets do; unlike crickets, they do not merely chirp but strike small sparks. Complications, as one can imagine, ensue.

    Silly thought: termites shuld be quite capable of building a big enough compost heap to achieve ignition, although I'm not sure how they would aerate it without cooking themselves.


    what about novae and supernovae?

    The only problem with those is that there aren't a lot of constraints. You can decide that a supernova will happen close enough to be dangerous five million years from now, or 20 million, or 100 million, or not at all... Same with asteroid or comet impacts: it's very arbitrary.


    When was the last time something weirdly different to everything else emerged? Something like grass, or tree-symbiotic fungus?

    Hm, good point. That article reminds me that nitrogen fixation is a beneficial ability that all too few plants have; apparently it is hard to get there from here. It seems plausible to imagine something evolving root nodule symbiosis as legumes have and spreading all over by taking advantage of niches other plants find useless. Such a plant family could easily be both diverse and wide spread in fifty megayears.

    But plants don't seem interesting to us in and of themselves. Does anyone have a favorite plant they'd like to see spread over the Earth? Can you think of a plant that brings along interesting commensual organisms that would generate interesting stories? Where does life go from there?


    Great minds just think alike I guess, now I have to try reading some of Niven's stuff, he's been referred to on this blog several times that I recall. My local library shows 140 entries, however, and I've sometimes been disappointed starting with an author's earliest work because it's too dated to sustain interest. Plunging right in with the most recent can miss a lot of back context, too. Got any faves?


    Some thoughts about scenarios/traits likely to help identify next evolutionary favorite:

    • Physical vulnerability – not completely adapted to the environment therefore has to take risks to survive;
    • Has or can acquire more than one trick – physical, physiological and cognitive flexibility, i.e., can run, climb, swim, dig, survive on varying diets, etc. doesn’t have to be best, just good-enough;
    • Cognitive flexibility in being able to size up a situation fast enough to choose among tactics;
    • Cognitive grasp of time (cause-effect relationships) allowing them to anticipate likely scenarios and prepare, and because there are seasons after all;
    • Communication/sociability – cooperation, inter-individual and inter-generational learning.
    • Life-span - has to live long enough to teach/raise kids, and benefit from taking a longer view (seasons). There are probably other necessary traits ...

    Immediately post human: No change, all creatures will do whatever they’re currently doing until a new equilibrium occurs. Next is random chance in terms of which creatures get a boost in some cognitive area. If this cognitive boost is immediately next to some already genetically seeded survival-predisposing trait (strength, speed, vision, etc.), then there’s a better chance for this new enhancement to be spread down and throughout the generations. At some point this trait might increase in strength or become recognized by the species as a selective advantage, therefore might be bred for in preference over other traits. If so, then this would increase the speed, strength (concentration) and within-species dispersal of this trait.

    Humans have never deliberately bred any animals – apart from fish in labs - for intelligence, so not possible to know how well or fast this can be done in the wild and whether this would be a sufficient survival advantage for that species in its natural habitat quickly enough.

    Artificial Selection on Relative Brain Size in the Guppy Reveals Costs and Benefits of Evolving a Larger Brain

    Highlights • Brain size responded rapidly to divergent selection in the guppy • Large-brained females outperformed small-brained females in a learning task • Evolution of larger brains leads to smaller guts and lower offspring number


    Been covered by one of my favorite books (and part of a "trilogy" (sorta-kinda)): The Butterfly Kid, by the late, lamented Chester Anderson.

    The "sequel", Unicorn Girl, by Michael Kurland, is just as wonderful.

    I have contacted Michael a few times, years ago, and he refuses to give me even on of the Blue Pills.


    "Humans have never deliberately bred any animals – apart from fish in labs - for intelligence, ..."

    Oh, yes, they have - sheepdogs. A specific kind of intelligence, to be sure, but intelligence nonetheless.


    Right. But it's not something that should be ignored on that timescale, though I would call it probabilistic rather than arbitrary, because it's not US that choose whether it happens!


    Fires == friction || lenses.

    Not. We'd leave a lot of stainless metal around after us.

    Lessee, there's this pretty smart racoon, and it's chilly, but it notices that this one spot of ground, during part of the day, is warm.

    [Sidebar: I have seen a cat chasing a laser point, and when the person with the pointer got tired of pushing the button, and the cat looked at the spot it was last at, at the laser holder, and come over and bat at laser pointer holding hand, clearly saying, "we are not done playing yet, turn it back on".

    A little dust, and racoon notes a pale light from the concave part of a metal sheet (crashed airplane wing? wrecked car?), and worries it free. And then sees it can point it during the day, and just right, and it warms what it's pointing at. And then, while aiming, it crosses an open area, and focuses on something many yards away... and smoke starts.

    The alternative is, to paraphrase what several folks have mentioned, is the plot of Quest for Fire, for the band's Sacred Fire Keepers.



    The point that plants don't seem interesting is, I think, kindof the point. The biota we live amongst is weird, but we're used to it so we call it normal. We think of fungus as just plants, because plants are familiar and mushrooms are (in culinary terms) just tasty, protein-rich vegetables. What would we think of a new phylum, if we were a new sentient species living megayears from now? We would just think of it as normal, because it would be.


    I find it difficult to believe there's going to be stainless steel -- let alone reflective stainless steel -- still lying around tens of millions of years in the future.


    Got any [Niven] faves?

    It's been decades since I read them, but I suppose I'd recommend the "Known Space" series.

    There are some short stories, IIRC collected in paperback, that were pretty good too. "Inconstant Moon" may have influenced my liking for Irish Coffee and hot fudge sundaes.


    Thank you for finding this. I've always thought that octopi not surviving reproduction was one of the evolution's cruelest pranks, and it makes me very happy to learn that it doesn't happen to all of them.


    While it's not so bad as it was a few years ago, there's still this desperate meme that wants to kill humans off. Either we're supposed to become extinct due to our own stupidity, or Science (capitalized deliberately, because this is a core tenant of evangelical scientism) will get so incredibly advanced that we'll no longer be human, evolution will no longer matter, and progress will deliver us from all those things we currently are anxious about, and all the stuff that they were chattering about a century ago before eugenics and xenophobia got nasty. Not that xenophobia and eugenics matter right now, of course.

    Here's the weird thing about humans: when it comes to how we adapt to our world, we've got two evolutionary pathways. We've got our genes, which don't evolve much faster than do the genes of any other big organism, and which are currently most strongly selected for tolerance to molecules like sucrose, lactose, and alcohol, and ability to survive pathogens. Then we've got our culture, which adapts to the environment at bacterial speeds. With culture, you can turn a farmer into an astronaut in a few decades. Hard to do that if you had to evolve hard-wired reflexes and developmental structures.

    Thing is, culture severely blunts the world's impact on our genes. It's radically easier and faster to teach someone to fish than it is to have them evolve flippers and closable nostrils, to pick one example at random. A fisherman may have the same genes as a farmer, even though, ecologically, they're radically different.

    That's why I think desires for human demise are premature. We're so much more likely to handle radical environmental change via cultural shifts that: a) somebody is likely to survive whatever catastrophe hits, and b) unless it's an incredibly bad catastrophe, enough people will survive that the catastrophe won't affect our gene pool.

    While I think it's unlikely that any of our descendants will be alive 50,000,000 years from now, just due to the probability of an extremely bad catastrophe between now and then, I'd say it's simpler to assume that we'll be around for quite awhile, and I'm guessing at least 5 million years, if not 10 million. They won't look like us racially, they won't have our language, culture, or values, but they will be genetically human.


    a) somebody is likely to survive whatever catastrophe hits, and b) unless it's an incredibly bad catastrophe, enough people will survive that the catastrophe won't affect our gene pool.

    I tend to agree, but the OP postulated, Let's imagine that it's about to get infinitely worse for everyone, and by December 31st, 2016, the human species is extinct. Cause: something minimally disruptive to the rest of the biosphere.

    So, to address the problem posed by OGH, whose blog this is, I think that we should play by the constraints he gave. People go poof without disturbing much else. Evolution in the suddenly changed circumstances goes its way, and how are things going to go during the next 5e7 years?

    Me, I think that the question of evolutionary time scales and the influence of the environment/surroundings on them is interesting. When does evolution go fast and when does it go slow, and why?


    Relevant bit from Cixin Liu: In the century-long history of Chinese science fiction, apocalyptic themes were mostly absent. This was especially true in the period before the 1990s, when Chinese science fiction, isolated from the influence of the West, developed on its own. Although I’m quite familiar with the history of Chinese science fiction, I can’t recall a single Chinese story or novel about the apocalypse in the period from the beginning of the twentieth century to the 1990s. The absence has to do with Chinese culture. Christianity in the West is vitally concerned with eschatology, but Chinese culture almost doesn’t have the concept of end times. In ancient Chinese mythology, there’s a beginning to the world (...), but no end point.


    It's radically easier and faster to teach someone to fish than it is to have them evolve flippers and closable nostrils, to pick one example at random. (Not in the letter of this thread, I know. Sorry.) This is true but soon not relevant because evolution is not what will be changing the human genome; humans (then transhumans etc) will be doing it directly, baring a complete and permanent collapse of technological civilization or a totally-enforced global prohibition on such changes. This will also be the case for any intelligent successor species (assuming the OP scenario) unless it suffers a similar fate.


    Thinking too much about evolutionary plausibility bogs me down, so i try without to find a species whose successor might make fire one day. We need breath control, fine motory skills, a heavy upper body and strong limbs, if we use Hs bucket list.

    Breath control: Pigs, coati (small bears), tapirs and elephants have trunks or other noses that look articulate to me. Otters and most marine mammals (star nosed moles, beavers ...) can close their nostrils. One of these could be a rudiment that leads to fine breath control. What is the use of blowing (when you don't have speech and need breath control for that)? MAybe to clean ones food of dust, maybe to blow up dust to better smell what's on the ground, maybe something social or intimate. Almost all birds can make some wind.

    Hands/fine motory skills: All or most bears, weasels and the like have something that might turn into a servicable hand. Is ther any path from hooves to hands? I can only think of reasons against, which is a pity because I kinda like the idea of recognizable pigs using tools.

    Heavy upper body/limbs: Favors optional quadrupeds, their forelimbs are dapted allready to transfer force downward: Bears most likely.

    From this list, I think a far larger successor of coati or otters could do it. Which is cool, because both are cute.


    OP: And we're going to see theory of mind everywhere. Predators, even social predators, probably won't evolve into a civilization, though perhaps they could block other species if sufficiently adept. (One possible counter-argument; predators that somehow start "farming" prey and then can increase their own density.) I'm thinking intelligent social opportunistic omnivores, on land, with manipulators like hands, where the theory of mind is primarily for support of competitive social interactions, and additionally for supporting preying on other species.
    Raccoons aren't social enough though perhaps they could evolve in that direction. Primates are, e.g. baboons (as suggested by anonemouse above). Social species in the Corvidae have everything but the manipulators but I don't see them evolving hands (or whatever).


    Brainstorming other tool uses we might see by animals: Transport: For any forager, beeing able to transport more than a mouthful must be worth a lot. So basket weaving or birds nests that can be carried could come up here and there in the future. Maybe a large flock of corvids hat forage a meadow, using baskets to carry the stuff home. They forage on foot and walk back to their nests, relying on large numbers for protection. In worst case, they can still fly away from a predator and leave their forage (which will ofcourse lead to opportunists that live by scaring of crow from their baskets).

    Any species with hand-like things and long hair (some bears) could braid primitive satchels into their hair, again to transport prey/forage or even their young.

    Den building animals could construct traps to protect their offspring - maybe blind tunnels with spikes in a badger den.

    Animals making clothes: some critters pluck sheeps wool (before the invention of shear, wool was gathered by combing or from bushes) to cushion their nests and distribute some of it into their fur by rubbing it over themselves.

    Ruminants spit pre-chewed food into carefully cleaned holes in the ground, some of it keeps because of the acidogenic gut bacteria. Enough grass, compacted thoroughly would ensilage on its own and thus keep. An important adaption would be bladder and anus control to not shit where one keeps the food.

    Foragers damage unedible plants with their hooves, to make room for edible grass, maintaining their pastures.

    Herd animals dig small holes (and compact the ground) in low points so surface water can gather, for drinking. On heavily sloped terrain these water holes will be longish, along the contour lines so this will also terrace the ground.

    Bears learn to systematically destroy beaver dams and feast on the fish that are then on the dry or at least in shallower water.

    Large cats learn to construct blinds, to hide while ambush hunting.


    Raccoons aren't social enough though perhaps they could evolve in that direction. Let me introduce to you the coati - basically a highly social 'coon without opposable thumbs (I think).


    Hm, thanks, I agree after a brief wikipedia look that coati are a candidate. Would need more evolution than e.g. baboons but perhaps a few million years would be sufficient.


    Can we have starfish terrans? Some ideas: Actual starfish: Some Starfish adapt to longer and longer periods out of the water and start tu hunt there, maybe raiding coastal birds nests or ambushing largert animals by lying in the sand. Imagine beeing surrounded by a 3m diam. Gorgons head. With their many arms and flat body they become surprisingly able climbers. Main defense against predators is maybe beeing poisonous or maybe they fight by turning the stomach inside out, then go for the eyes.

    Arthropods of unusal size: Beetles or other crawlies figure adapt to bearth even when (far) larger. My fave wood be huge (house size?) woodlice/pill bugs - they eat whole forests and live on symbiosis with funghi on sterois (the giant lice destroy wood mechanically and spread spores, then feed on the fungi). Obvious inspiration.

    Cthullhufant: Star nosed moles grow to hippo- or elephant size, the nose tentacles grow along and become major manipulation organs. Our be-tentacled mega-moles are the critters with the poorest eyesight on the great steppes, but live quite well (thanks for asking) on all kinds of burrowing rodents.

    Some shark-descendants become snake-like land dwellers, their super powers include electrical senses, taste by skin and an endless supply of teeth.

    MEanwhile, elefants take to the rivers and lakes. You mostly see the snorkles.

    Eusocial ants start to settle an hairy ruminants, mostly feeding on nor quite digested foodstuff (both ends) milk, and other parasitic insects and worms.

    Some snakes develop gripping appendages on their bellys, one very underdeveloped pair for every pair of rips. This allows to carry prey, nest building material or eggs and opens new climbing possibilities. OTOH the snakes now move like caterpillars.

    Thermites start to build dams, not mounds, the reservoirs provide for small ecosystems in otherwise drier steppes and also feed the thermites.

    Some flowers adapt to grow out of ruminants behinds. I'd better quit now.


    Thermites start to build dams...

    Presumably in narrow canyons, where it's easier to block the stream with a few well-placed charges...

    (Sorry, couldn't resist.)


    Social species in the Corvidae have everything but the manipulators but I don't see them evolving hands (or whatever).

    How about bats? I discovered over on Wikipedia that there are a lot more bat species than I appreciated, and many of them have some ability to grasp things. Like birds they tend to be too small now; growing much larger would cost them the ability to fly and make them uncompetitive with existing animals. The idea sounds fun but I'm not seeing a good development route.


    Well, we did ask the question how termites can ventilate a compost heap without boiling themselves. Not at all, but we have reserves applies ...


    Cthullhufant: Star nosed moles grow to hippo- or elephant size, the nose tentacles grow along and become major manipulation organs.

    That is disturbing and awful! Also, quite reasonable and practical. Imagine them basically like any large grazing herbivore in body form, plus having flailing octopi on their faces, and all too likely to become clever and verbal.

    Thanks, I'm going to be a while getting that image out of my head. Have you seen those things? Yikes. grin


    Since I'm on a social insect kick today, I'll run with that. Ants and termites aren't going anywhere. What if some species stumbles onto a way to record information in the physical structure of its hive or some other inanimate object? The bee dance can be seen as a proof-of-concept demonstration that social insects can transmit information from one individual to others. It's not unreasonable to imagine a species building some kind of structure that served as a lasting monument, sending messages like 'good meadow 2km NE' or 'water 1km S' into the future; any breed that suffers heavy population losses in winter could benefit from such a thing.

    We already see social insects creating things beyond the comprehension of any single insect, from the regular geometric hexagons of a honeycomb to the efficient ventilation systems of tropical termite mounds. Given their observed abilities both creating and interpreting such solidified signals seems to be plausible.

    Such a talent seems likely to be an advantage that helps its carriers spread and prosper.

    Yes, I'm working up to writing without speech, even without rational thought in the sense humans have it. Such arrangements could become sophisticated very quickly, giving individual insects useful programming; I don't need to belabor to this audience how programs can be made of very simple instruction sets or how evolutionary programming can spit out hideously complex software. This would give the hive and the species a cultural heritage without any individual necessarily being noticeably smarter than any ant, bee, or termite of our era. Cross-cultural exchanges would happen between groups able to interpret each others' programming language, which would not necessarily be the same as species that would interbreed. (Imagine a young queen landing on a hollow log and discovering an old hive filled with the Wisdom of the Ancients, some of it dating back over ten years...) The obvious limitation is not in storage space but in how much memory any single insect can devote to processing; there could be many millions of years where hive cultures plateaued because no species had developed a multiple-ant parallel processor.

    So...imagine social insects without abstract thought but with writing and 'culture.' What follows from that new development?


    Eusocial ants start to settle an hairy ruminants, mostly feeding on nor quite digested foodstuff (both ends) milk, and other parasitic insects and worms.

    I like this. It could easily become a symbiotic relationship. Predators could learn that targeting the Seething Sheep of Sierra Leone means getting a muzzle full of angry biting things! The host could enjoy protection from ticks and other bloodsucking parasites while the insects got some protection from predators and weather.

    Thinking it over, I'm not sure ants are the best bet for this; while wildly varied, ants tend to burrow for their colonies rather than constructing new ones from their own materials, and even a buffalo or mammoth might not provide enough foraging area. Being left behind when your home wanders off would be bad. So how about a more mobile social insect? Imagine the surprise when a predator leaps out at a grazing herbivore to discover it's full of bees!


    Squirrels most likely. They're social, have sort of hands, and practice something akin to agriculture. Also they're widespread and numerous, especially in proximity to humans. Previously human environments will be highly enriching. They're known to be very clever at getting where they want to go. They just need to get bigger and start hunting in carnivorous packs. The problem with that is the prey pattern of the eyes. So they'll need to get parallax by sharing visual information between squirrels. Maybe telepathy (aka, ultra-sonic high- information-density chittering). Also some breeds fly. That will be helpful.


    Keith Masterson noted: "The only organisms I recall which require the presence of fire as part of their life cycle are certain trees whose seeds won't germinate until after exposure to high temperature"

    You're forgetting a whole raft of what are called "pioneer species" that require some force (here, fire) to eliminate the trees so they have access to mineral soil and sunlight without having to compete with the trees. If you've ever seen a cutover or post-fire site, you've undoubtedly seen fireweed (Epilobium spp.) growing there; it's kind of the poster child for boreal pioneer species.

    But it's not just plants. Many insects are also heavily fire-adapted and couldn't survive without fire. This includes the group of beetles responsible for getting wood decomposition started, which in turn leads to a cascade of follow-on effects for specific fire-adapted fungi and bacteria, reptiles, amphibians, birds, and mammals. Many rich ecosystems couldn't exist without periodic fires, and biodiversity often declines in the absence of such disturbances.

    Moreover, plants and other organisms coevolve to survive and flourish after fires. Back a few years, when I was in grad school, there was a coevolution hypothesis in which (oversimplified) pure stands of lodgepole pine collaborate with a group of bark beetles to commit suicide by beetle, leading to enormous amounts of dead wood, leading to catastrophic fires that erase the forest and create conditions highly suitable for -- you guessed it -- lodgepole pine.

    There are parallel processes in grasslands, some wetlands, and most biomes other than those under water. G

    Fire adaptation is ubiquitous, not just something for a few trees.


    Hypergolic insects sound quite plausible when you consider that the bombardier beetle is half way there already.


    If you want an odd idea for a culture that doesn't involve fire, consider the following:

    Mixed flocks of parrots. Huge flocks of multiple parrot species.

    We already know that African grays are pretty intelligent and possibly more social than humans. It's not clear whether the fact that they flock into the hundreds means they have a very high Dunbar Number, or if they have some social subdivision that we don't see in those flocks.

    In any case, we've mixed parrots and other birds (pigeons, corvids) from all over the world. What if they collectively evolve something resembling a civilization composed of massive flocks of mixed species, African grays, cockatoos, macaws, parakeets, whatever escapes into the wild. They collectively have a culture, not with one dominant sapient critter, but with a large bunch of pretty smart birds doing different things and living together.

    Obviously they wouldn't be technological, because pyrogenesis is a hard place for them to evolve into. They're too small to make friction work, even without those singular beaks. On the other hand, millions of parrots can pretty radically alter a place, possibly even to their specifications. They already seem to have the rudiments of culture, and they learn extremely fast.

    Anyway, consider a civilization composed of a massive heterarchy of intelligent birds. What should we call it? Perhaps a polyculture?


    Eusocial ants start to settle an hairy ruminants, mostly feeding on nor quite digested foodstuff (both ends) milk, and other parasitic insects and worms.

    I came back to this because I had an idea for the host creature: sloths. Yes, I know, but follow along. I remembered that some sloths actually turn green because they have algae in their fur, and a quick check of Wikipedia reveals, "Sloths make good habitats for other organisms, and a single sloth may be home to moths, beetles, cockroaches, fungi, ciliates, and algae."

    At this point it sounds downright reasonable for ants to move in. There could be any number of creatures symbiotic with ants also using sloth fur as a home, and it's not as if sloths are known for wandering off quickly. Ants which left the sloth to go foraging in the tree could easily enough find their way home. Sloths are common within their limited geographic area so they're likely to survive humanity's extinction just fine.

    "Because of the algae, sloth fur is a small ecosystem of its own, hosting many species of non-parasitic insects." Sounds like an open door for some innovative ants to me.


    Thermites start to build dams, not mounds, the reservoirs provide for small ecosystems in otherwise drier steppes and also feed the thermites.

    Delightful typo aside, it would seem on the surface that termites and beavers have much to offer each other. Beavers gather vast masses of wood into one place and, deep inside, the mounds have a chamber that remains survivably warm even through the coldest winters. Termites can get into places beavers can't, could eat beaver parasites, and some are good at constructing smooth walled water resistant structures (though I'm not sure what termite constructed thing beavers might care about). It might be that the termites were merely commensal with beavers and the rodents wouldn't get anything much from the insects.

    For whatever reason this doesn't seem to have happened yet. Does anyone have any guesses why?


    Animals that survive & those that don't ... Recommended reading: Richard Fortey : "Survivors" Pub Harper/Collins 2011 ISBN 978-0-00-720987-3

    Includes: Stromatolites, Velvet Worm, Horseshoe "crabs", terreret frogs, lungfish ( & hagfish & lampreys ) etc. Well worth the read.

    193: 172 and #186. Squirrels evolving into super-intelligent tree rats has me worried. I started thinking about an intelligence arms race between the squirrels and the Musteloidea that prey on them. Except that successful Pinemartens lead to grey squirrels dying out and red squirrels thriving because the reds can get further out on thinner branches where the Pinemartens can't get them. So the downside of bigger brains is greater predation just due to weight and body size. Of the other Musteloidea, I'm not sure Badgers have much reason to get cleverer, but the idea of them setting traps for the cull hunters in the UK appeals. Having them shooting back might be fun, but hidden pits with punji sticks seems more likely. 174. Re, Rooks and crows using baskets to carry forage. This clearly needs a crowd funded Etsy shop for crow-suitable messenger bags. But how do you go about teaching and training them to use our gifted carrier bags? They're already surrounded by discarded crisp packets and plastic bags and haven't worked it out yet. Or have they? Could we train them to do litter picking in return for some reward? 189. Mixed species bands of monkeys is already a thing. Canopy, mid tree and ground-dwelling working together in a troupe with cross species communication. Which makes me wonder if now (in evolutionary time +-1m years) is intelligence time when nature intelligences and homo sapiens was just the first of multiple leaps across the intelligence singularity.

    it would seem on the surface that termites and beavers have much to offer each other... For whatever reason this doesn't seem to have happened yet. Does anyone have any guesses why?

    If I had to hazard a guess, I'd say that I'm not sure what the beavers would get out of it, given that the termites would be eating their building materials and homes and competing with them for food. (Wouldn't it be kind of like our relationship with termites? After all, we gather masses of wood into one convenient location and keep things warm inside...)

    I also suspect a beaver dam might be too wet and waterlogged for termites (it's mostly underwater on one side, after all).


    Well I'd imagine that if the animals are intelligent they will all be real confused by Mt Rushmore

    If it's still recognisably a carving: OK, it is made of granite, but even so it could get covered by lichens and mosses, and freeze-thaw action and wind scour will have effects in millions of years.

    Possibly so will being washed down with dilute carbonic acid if the CO2 levels remain high for significant time.


    Crow school, leave out food for crows in front of a display running looped animations of crows doing things within the capabilities of avian anatomy that might be useful to crows. Might be fun to watch, and wouldn't be any more whacked than releasing starlings in Central park.


    So...imagine social insects without abstract thought but with writing and 'culture.' Loving this one. An evolved instance of something like Searle's Chinese Room. But why not abstract thought? Presumably the insect colonies are Turing Complete.


    I suspect there are a bunch of reasons for beavers and termites not getting along.

    One is that beavers have been killed out of the warmer end of their range, and termites don't do cold worth a damn. Right now, their ranges barely overlap, and the termites aren't going to get noticeably more cold tolerant any time soon.

    A second is that, while termites need a bit of water, they're not as aquatic as beavers are.

    A third, already mentioned, is that beavers need the thermal and structural protection of the lodge, especially during winter. It needs to keep out grizzlies, after all. Something that structurally weakens a lodge is not a good thing.

    That said, beavers actively tolerate muskrats, mice, and frogs in their lodges during the winter, so beavers forming relationships with other species is totally plausible.


    One of my favorite candidates for climbing the evolutionary ladder: the beaver. Beavers' building/engineering skills appear to be taught rather than hardwired. They are able to co-exist amicably with other species including allowing other furry critters to overwinter in their lodges. Only thing is: do they have language, and if yes, how complex is it.

    Adaptability/trying new things ... although every reference I've clicked says that beavers are pure vegetarians, here's a film showing that at least one beaver enjoys fish. (Brain-food!)


    You arguably don't have to be Turing complete to be intelligent. Humans certainly aren't.

    Sure, a human with appropriate training and concentration can simulate a small part of a computer for long enough to perform basic debugging tasks but the infinite infallible memory isn't there.

    I'm not sure that being a Turing machine with infallible memory is particularly desirable from an evolutionary point of view - basilisks would probably be real for starters.

    Termite colonies would probably do better than us on the memory front - maybe they could debug programs properly :)


    Possibly. I suspect the more general answer is that ice ages cause a lot of climate changes. This favors species that are highly adaptable, and the simplest way to be adaptable is to have a culture. In non-human terms, culture simply means that an animal has to learn to become fully competent, that it doesn't rely entirely on instinct to make a living. In this version, everything from cats to crows, apes, coyotes, raccoons, bears, elephants, and many others are cultural animals. Humans, of course, take this to an extreme, in that we absolutely require a huge amount of learning to reach adulthood, and the results of extreme isolation on children are profoundly bad.

    Whatever happens with anthropogenic climate change, the planet is stuck with ice ages for at least the next million or more years, and during that time, I suspect that smart species will be favored. It's not at all clear whether that will be the case when plate tectonics takes the planet back into a consistent hothouse. If the climate is boringly consistent over millennia, might species that run on instinct not reproduce more than those who have to waste a good part of their lives learning to be competent and depending on their parents for support?

    As for an intelligence singularity, I'm not sure what that means any more. The people who work on animal intelligence are coming to the conclusion that there are many different traits bundled together as "intelligence." Like evolution, it's a tree, not a scale. We've been misled (does it go back to Aristotle?) that intelligence is a single number, but it really isn't. Yes, humans are quantitatively different than other large vertebrates. But when you look at the elements of intelligence, there are some, especially with memory and spatial reasoning, where we aren't as good as the average squirrel, chimp, pigeon, or dolphin.

    That's a big reason why I focus on fire, because it really is the place where humans are absolutely different than everything else. We don't have to weeble away at how we got somehow got intelligent, then we got fire, then we took over the world. I'd suggest that it was the other way around. Kanzi the bonobo has no trouble with the concept of fire, so arguably you don't need a brain any bigger than a bonobo's to make a campfire, cook your food, or make tools. The nice thing is that fire makes food more digestible and also helps you make all sorts of cool new tools. Once you've unlocked fire in the game of life, it helps your species level up both in tool use and in resources that you can use to support more brains. At that point it's a positive feedback loop, and that's the kind of thing that would make any pyrogenic species qualitatively different from its competitors, whatever kinds of intelligence it initially had.

    The downside of this idea is that it's not that easy to make fire. If we want to look for the precursors of the next pyrogenic species, you've got to look for a cultural species that has the precursors of hands and shoulders capable of making a fire. At this point, that looks to be limited to primates, but perhaps in 50 million years, some procyonid (like a raccoon or coati) will evolve in that direction. Or some other primate (capuchins, perhaps) will head in that direction.

    I was playing with mixed groups of species simply to try to get to a wildly different pattern. Is it possible for a coalition of species to be collectively "intelligent," or at least to collectively run the world? I don't know, but it's an idea to play with.


    Charlie, I'm sorry, Disney already figured out the answer to this scenario. See "Zootopia". :)

    (As for the venom thing, "Night Howlers") :)


    "We've got no idea how common our combination of verbal skills and dexterous manipulators might be. It's happened exactly once in Earth's history and it's not immediately obvious how likely it is to happen at all."

    Actually we don't know that at all. We could easily fit a near industrial smart dinosaur civilisation (or two or three) into Earth's past without having any evidence for it today. We assume we're the first, and we're probably the first to make widespread use of nuclear power and plastic but beyond that its an unknown.


    of note:

    "Ross 248... in about 31,000 years it may be the closest star to the Sun for several millennia, with a minimum distance of 0.927 parsecs (3.02 light-years) in 36,000 years. Gliese 445... in about 40,000 years it will be the closest star for a period of several thousand years. Gliese 710 ... indicate that it will approach within a very small distance—perhaps under one light year—from the Sun within 1.4 million years

    In a time interval of ±10 million years from the present, Gliese 710 is the star whose combination of mass and close approach distance will cause the greatest gravitational perturbation of the Solar System.

    HIP 85605 is also concerning. Its spectral type and trajectory are not fully understood. More-accurate astrometry is required to determine the distance to the star, and thus if it will pass close to the Sun. It was estimated in 2014 that HIP 85605 could approach to about 0.13 to 0.65 light-years (0.04 to 0.2 pc) from the Sun within 240,000 to 470,000 years."


    In that sense, no bounded system can be Turing complete. However, there is a perfectly reasonable sense in which we (probably) are, as a species.


    I'm not so sure that's true. The big evidence is that most of the coal we used in the industrial age was Carboniferous, meaning it was laid down before the dinosaurs even evolved. Similarly, we've depleted huge iron deposits that are massively older than the dinosaurs. While I agree that a few kilometers of erosion and deposition over 50-100 million years makes a huge difference in what is minable and what is not, I don't see how an industrialized civilization could have existed on this planet without depleting the resources we used to create our own industrial civilization.

    Additionally, there's no evidence of industrial artifacts in the Mesozoic, and there are a lot of rocks and even some fossil soils from that era. Like it or not, we're making the kind of mess that will show up in rocks for hundreds of millions of years. Plastics may largely vanish, but bronze and other slow-corroding metals like nickel won't. Glass may be too cloudy to see through, but it will be around.

    Remember that the K-Pg band is this thin layer of iridium-enriched clay that's been found in deposits of the right age all over the world. Industrial civilization would leave a similar mark, but no one's seen anything like it yet.


    Re: 'In a time interval of ±10 million years from the present, Gliese 710 is the star whose combination of mass and close approach distance will cause the greatest gravitational perturbation of the Solar System.'

    Wow! - Thanks for this.

    Any idea what these perturbations are likely to be? (Oort cloud destabilized with more rocks careening into each other becoming planetesimals large enough that if bumped out of orbit (sunward) could wipe out Earth?)


    Which is why I went with 'near industrial' :)

    Obviously the bigger and the more advanced the posited civilisation the less likely it is but my main point was to echo your comments about the deep future into the deep past. We're really working with limited evidence as we go back 50m years let along 100m or 300m.


    Our machines are, kind of. A human with a stack of paper can painfully execute programs. As individuals we aren't even close.


    Not an expert but Oort cloud destabilisation seems a likely pick. For a real doomsday scenario something that perturbs planetary orbits could be fun - how likely that is I'm not sure anyone has a good answer.


    Yhere's more on the wikipedia page for Gliese 710

    "Bobylev estimates that it will pass within 0.311 ± 0.167 pc (1.014 ± 0.545 light years) of the Sun.[5] There is even a 1/10,000 chance of the star penetrating into the region (d < 1,000 AU) where the influence of the passing star on Kuiper belt objects is significant.

    ...Using the newly acquired Gaia data, the closest approach of the star has been revised to 0.205 +/- 0.07 light years, possibly coming as close as 9,000 AU from the Sun."


    ... it cut off the important line;

    "There is even a 1/10,000 chance of the star penetrating into the region (d < 1,000 AU) where the influence of the passing star on Kuiper belt objects is significant"

    [[ Note: if you want to include a literal < symbol, type in &lt; - mod ]]


    Squirrels? NO! I absolutely deny the damned tree rats ever become more than they already are.



    Re post 165, I was not suggesting even a million years from now. However, the fragment I wrote could certainly take place within a century or three... and that assumes that critters aren't already aware of some of these things.


    From the same source .... 'More recent calculations by Bobylev in 2010 suggest Gliese 710 has an 86% chance of passing through the Oort cloud,...'

    That's a pretty high probability of something 'interesting' happening if Gliese 710 hangs around for more than a few years.


    The bit it kept cutting out was that closer than 1000 AU the influence on Kuiper belt objects is significant


    Re: 'Continental drift ... geologists speculate that between 50 and 200 MYa from now we can expect ... around the north pole ... a new supercontinent, Amasia ... alternate model ... Pangaea Ultima.'

    A couple of questions:

    How does continental drift impact axial tilt or is it the other way around, i.e., axial tilt influences how landmasses might collide/coalesce? (Why I'm asking: axial tilt is a big factor in 'seasons'.)

    Also: Where exactly is the Arctic and Antarctic melted ice going? Is it spreading out uniformly across the oceans, e.g., every ocean's depth increases by exactly 1 meter? Or, is this melted ice pooling in/favoring one part of the surface of our 'globe' over another. (If so, why?)


    Im not so sure you aren't over egging things slightly. I would go as far saying anything that leaves point evidence should be discounted as unlikely to be found across the surface of an entire planet. How many fossils do we have from all the things that have previously existed across geological time? Very very few statistically speaking.

    We should probably only be considering evidence of a similar magnitude to the K-Pg band. Which off the top of my head narrows it down the very small list of things that are being considered as markers for the Anthropocene.


    Its hard to get good numbers - I did a quick search and found a slate article from 2009 ( ) Which claims 3,000 'full' dinosaur specimens in US museums and 'triple' that number uncollected world wide. Call it 10,000 for the 165 M year dinosaur period and that's one for every 16,500 years worldwide (worse when you consider finds often cluster in specific locations that promoted preservation.

    Over these sorts of time frames even long lasting artifacts are going to disappear to geological processes, whole regions can be buried by volcanism or flooded and even if we did find a bronze tool absent context its open to question if it'd even be identified or recognised as a technological artifact (and then there's the decades of academic argument about Dr Crazy's wacky dinosaur theory and how the carbon dating got contaminated and it couldn't possibly be true).


    Fossils yes, rocks no.

    The big issue at least to me is coal. Any fossil fuel cooks away if it is buried too deep in the crust. In order for there to be a lot of Carboniferous coal in, say, the Appalachians or England (both of which are quite old), they needed to somehow be buried so deep that a previous civilization couldn't find them and mine them out (which means basically on the order of a few kilometers. The deepest coal mine bottomed out at 1550 m), yet shallow enough that they would be uncovered by subsequent erosion. I'm certainly not a geologist, but that, seems like a fairly small window to me, given that we're talking about a period of up to 100 million years and erosion can strip off over a kilometer of rock in that time.

    The general point is to look for modern industrial resources that are considerably older than the Mesozoic, then figure out if there is a way for geology to have hidden them away in the Mesozoic so that the paleosapients would have missed the bonanza beneath their feet and left it for us.

    Similarly, future sapients will have to depend on the resources we've managed to miss over the last 200 years of the industrial revolution, plus whatever regenerates between now and then, which is basically a bit of coal and oil, plus the junk we left behind. The remnants of our cities and landfills could be used as metal mines, if they get buried fast enough so that they don't rust away. It will confuse the hell out of future geologists to find things like aluminum, iron, hydrocarbons, copper, and so on in a matrix of carbonates and hydrocarbons, but that should only set their geologic science a few decades. A century, tops.

    That's actually another point: there's no known modern mine in a formation that looks anything like a modern landfill or urban infrastructure, even though forests have been preserved as fossils. That's odd, considering how big modern cities are.


    You don't have to be big to be a sophisticated civilisation and you don't need coal either. Take the Khemr and the Mayans as examples, both highly populated, complex social structures, impressive agriculture and some sciences. They both disappeared practically a second ago on the time scales we're discussing and we're still in the process of discovering whole cities we didn't know excited. Give it a 100 M years and how much evidence of Mayan civilisation would be left?

    I agree with you on deep mines and usable resources I'm mainly aiming at the assertion that "our combination of verbal skills and dexterous manipulators might be. It's happened exactly once in Earth's history". Its something we just don't know.


    How does continental drift impact axial tilt or is it the other way around, i.e., axial tilt influences how landmasses might collide/coalesce?

    No connection at all, as far as I'm aware. Variations in axial tilt (obliquity) are due to gravitational interactions between the Earth, the Moon, the Sun, and other planets. Changing the obliquity requires changing the direction of the Earth's angular momentum vector. This is something you can do with torques from outside, but it's hard to see how you'd do it with anything internal to the Earth.


    That's a reasonable assertion. I personally don't buy it, because things like encephalization do seem to generally increase through the fossil record, but it's not entirely impossible that a big brained something could have lived and died without leaving a trace. Personally, I'm not sure you can halt at the Mayan arbitrarily--they were stuck with basically no metals, while the predecessors to the Inka were casting bronze and so were the Aztecs a bit later--but it's not impossible. To get that kind of invisible sentient species, you'd need either a localized intelligent species, sort of like a New Caledonian crow writ large, or more likely something that was a wide spread hunter-gatherer that died out without becoming wildly technological.

    However, if we're talking about a species that got to where we are now technologically, that would leave big marks all over the geological record for its time.


    Be careful with bad-mouthing Squirrels here.


    Genuinely intruiged by this, posit that no other traces of mankind remain but for our coal consumption - what evidence would a successor species be able to point to that would indicate a period of intensive coal consumption rather than just say the status quo?

    Ie we know large amounts of coal exist because we have gone out and surveyed for it, what if our surveys had forced us to conclude coal was rare, would there be enough supporting evidence such as volume of fossilised plants to determine that coal should be more plentiful?


    ...if we're talking about a species that got to where we are now technologically, that would leave big marks all over the geological record for its time.

    I concur. There's space for verbal hunter-gatherers but even an extended stone age tool maker more than a few million years ago looks dubious; stone knives and spear points are hard to mistake for anything else and they last a very long time. (Never mind the coal deposits, what about flint and obsidian[1]?) The oldest stone tools are over a million years old but they're found where hominids could have used them.

    1) Maybe there were obsidian knapping dinosaurs; it's metastable and over geologic time changes into other stuff. Explaining the lack of flint tools is someone else's problem.


    Heteromeles (206) noted: "I don't see how an industrialized civilization could have existed on this planet without depleting the resources we used to create our own industrial civilization."

    I'm assuming you mean a past pre-human civilization, but the same logic largely applies to post-human species that take over the mess we've created. That being said:

    By means of the three R's: A civilization that has difficulty obtained a resource (e.g., iron) will reduce use of that resource until it becomes more readily available. They will also reuse the resource. Finally, they'll recycle products that contain the resource.

    We don't reduce resource use because we haven't run out of easily and cheaply exploitable sources of most things yet; we don't reuse (most) things because it's cheaper to throw them out and create new ones; and we don't recycle (as much as we should) for the same reason.

    These are all plausible and relevant mechanisms for a post-human species that has to deal with the depletion of fossil fuels we've created. Much of our ability to be incredibly wasteful results from cheap fossil fuels that make it easier to exploit than to 3R. To achieve comparable profligacy, that future species will need to (re)invent cheap and efficient harvesting and storage of renewable energy (e.g., solar power plus batteries). That won't be as easy as using coal and oil.


    That's a big reason why I focus on fire, because it really is the place where humans are absolutely different than everything else.

    This. First round candidate eliminations: Anything that lives underwater, or is too small to haul around several kilograms of wood, or has no way to manipulate tools. (Goodbye octopi, crows, and horses.) Raccoons are a little small but could get bigger easily and quickly. Bears could discover fire but might not care. Maybe that's an un-asked question lurking in the suppositions that we should examine: what creatures want fire?

    Remember also that creating fire is a different thing from using it; our own ancestors used fire long before we could create it upon command.


    Also new avenues of domestication. We're already seeing various monkeys domesticating wolves and dogs.


    It's been well established that both cetaceans and apes "get" video and pictures; I'm waiting for some bright soul to build dolphin- and chimp-operable video cameras and editing equipment.


    One of my favorite candidates for climbing the evolutionary ladder: the beaver. Beavers' building/engineering skills appear to be taught rather than hardwired. They are able to co-exist amicably with other species including allowing other furry critters to overwinter in their lodges. Only thing is: do they have language, and if yes, how complex is it.

    Hm, yes. Other rodents too of course, but the beaver is doing good learned engineering now. I'll toss out the idea that fire use might come later; what beavers really need are hand tools. Suppose that after humans go some of the surviving beavers grow into larger breeds; they're already the second largest rodent, averaging about 20kg, and it's no stretch to imagine that doubling to 40kg. That's plenty big enough for a sapient tool user. Hopefully they also develop longer lifespans!

    While humans invented spears early on, I imagine clever beavers inventing axes and saws. Or, even more advantageously, ropes! They could have some really impressive fiber arts creations without needing much in the way of stone tools; ropes, nets, and pouches are all obviously useful to a tool user wanting a more luxurious beaver lifestyle.

    Smart beavers might stumble onto agriculture through cultivation of fiber yielding plants rather than food. Even the current beavers are surprisingly skillful land managers; verbal beavers would probably do better at that than we, as evolved chimps, have been doing.

    One limit I see is beaver socialization; while they have fairly large families they don't gather into the extended bands we primates enjoy. There's probably a population sweet spot here and I don't think we have enough information to know where the boundaries are. There's also the point that existing beavers don't have the vocal aparatus we do but that's a solved problem. Trying to imagine their version of our own stone age tribes makes me think of sprawling river populations, with many fewer people per square mile than humans would have but with better long distance communications, more willingness to cooperate with the neighbors (as long as everyone kept their distance), and probably some kind of socially accepted courier.

    A common rite of passage might be serving a year as a mail-beaver and general freight hauler!


    SFReader: According to Darren Naish (@tetzoo) there is no such thing as a pure herbivore. He retweeted a photo of a cow eating a bunny just a couple of days ago as an example. Opportunistic supplementation of protein and minerals is apparently pretty universal, even over and above the eating-the afterbirth thing.. So increasing opportunities, or deficiencies driving an animal to look for supplements, could lead to dietary drift.

    Similarly, pure carnivores are pretty rare. Even wild and feral cats, which are proverbially obligate carnivores, depend on trace nutrients supplied by the gut contents of their prey. Substituting fire (as our ancestors did) for the preprocessing provided by mouse guts opens up a lot of options.

    And there is always individual variation: I had one cat that had been a literal alley cat who apparently was never told about the obligate carnivore thing: she loved pasta with tomato-based meat sauce, and, oddly, cooked peas, and wanted table scraps even when there was plenty of actual cat food available. (Dogs' desire to share people food may be partly a pack-bonding thing, but I'm not sure that applies to cats.)


    " extended stone age tool maker more than a few million years ago looks dubious; stone knives and spear points are hard to mistake for anything else and they last a very long time."

    I'd disagree with that, million year old stone knives and spear points are hard to mistake for something else, but hundred million year old? And then there's the question of dating given we assume any stone tools we find are no older than three million or so years. And people tend to overestimate how much we've found per the article above ~3000 good dinosaur examples found out of an estimated ~10,000 world wide for a 165 million year period. We don't even have good evidence of their relationships its all pretty much 'well this looks sort of like that might 50 M years later' - not that we have a firm grasp on looks either, remember when feathers were a heterodox idea?


    I had one cat that had been a literal alley cat who apparently was never told about the obligate carnivore thing...

    Must have been related to my childhood cat who adored green onion/scallion tops.


    Thread drift having set in (one might hope that OGH will introduce corrective admonitions) and the topic of far-future successors figuring out that there were Those Who Went Before being discussed, how about open-pit mines in stable geologic settings? The successors might need a bit of geological ability, maybe 19th Century level, but open-pit mines are quite big and obviously unnatural.


    "Kanzi the bonobo has no trouble with the concept of fire, so arguably you don't need a brain any bigger than a bonobo's to make a campfire, cook your food, or make tools... Once you've unlocked fire in the game of life, it helps your species level up both in tool use and in resources that you can use to support more brains."

    Kanzi can dig fire as far as using it goes, but the bald wizards have to give him a magic wand to make it with. Take away his lighter and he'd be screwed unless he was lucky enough to happen across something that had taken fire from natural causes.

    And IF fire-making has to be done by friction, he'd remain screwed no matter what he did. It'd be his distant descendants - bonobos who had used fire to enhance their nutrition and develop bigger brains - who would eventually get the idea of making rudimentary tools for something like primitive carpentry, and then discover that they could be modified to start fires.

    Frictional fire-making tools - drills, ploughs, saws - are basically woodworking tools put to a different purpose. And I reckon that the woodworking (stoneworking, boneworking, whatever) use must come first. Because frictional fire-making is such an unlikely thing to discover any other way. You can rub things together all day long if you're bored enough and all you'll get is blisters. To get any noticeable heat at all you have to keep rubbing precisely the same very small area very hard for a very long time, which you won't do or be able to do unless you've already had reason to make a drill or saw to bore or cut things. Sawing or drilling something to remove material, and going at it hard to get it done quicker, is about the only thing you can do with your hands that you can discover will make smoke.

    Now, how about a land-dwelling descendant of an electric eel, or a land animal that develops the same muscles-into-batteries modification, that can start fires by electrical heating...


    "One is that beavers have been killed out of the warmer end of their range, and termites don't do cold worth a damn."

    Well, there's your reason for termites wanting to symbiose with beavers, right there - they want the warmth of the beavers' lodges. Not sure what the beavers would get out of the termites though.


    "I imagine clever beavers inventing axes and saws."

    I'd imagine that those are just what they wouldn't invent. Nor would intelligent moles invent spades. They can already perform those functions perfectly well using the parts of their bodies adapted for the purpose.

    Human invention (in the early stages) tends to be for purposes for which we do not have a built-in anatomical adaptation. We don't have any natural armament, so we invent weapons. We don't have wood-cutting teeth, so we invent saws. Things that we can do for ourselves we do do, to begin with. Then we invent slaves. Inventions to do things humans can do without them don't tend to proliferate until after we've decided slaves are a bad idea.


    "Maybe that's an un-asked question lurking in the suppositions that we should examine: what creatures want fire?"

    I agree; I suspect a lot of them don't, being sufficiently well adapted that they get on fine without it.

    Those that do, or might: Meat eaters dwelling in an area subject to wildfires, who discover that precooked meals are tastier than raw. Similarly, pigeons and seagulls, who have discovered that fish and chips from the chippy are tastier than raw, and with the disappearance of humans have a reason to want to cook them themselves. Creatures that don't like the cold, such as Japanese macaques without a convenient hot spring. Maybe some creatures which currently hibernate, although there is the food supply reason for hibernating too.


    The apparent advantage of fire is that, in the signs of Koko the Gorilla, cooked food tastes better. Reportedly there's a study out there where two groups were fed exactly the same rat chow. One group got it raw, the other got it cooked, and the group with cooked food gained more weight. The advantage to cooking is that it's a form of external digestion, and you may have to spend less energy stoking the fire that cooks the food than you would digesting it. Cooking can also detoxify certain foods.

    Granted, not every animal needs to cook food. A hummingbird would probably die of starvation trying to cook sugar water for its own consumption (which is what we do for them). Still, there's a theory out there (Richard Wrangham's Catching Fire) that animals that use fire can develop proportionaally bigger brains. The idea is that both brains and guts are resource intensive organ systems. If you can outsource part of your gut function to something like fire, you can then shrink your guts and expand your brains. Wrangham cites the ribcages and skulls of modern apes and extinct hominids, and he's got a point. In the hominid fossil record, the expanded lower rib cages that go with big guts disappear as brains get bigger (starting in the Homo line), and there's evidence for fire use from Homo erectus on.


    Yes, I agree with all that, but the important point is in the first sentence: cooked food tastes better. That's the advantage that will get creatures motivated to start cooking their food in the first place. Otherwise they aren't going to see any point going to all that trouble. The gut/brain tradeoff thing happens afterwards, long-term, over several generations that have made cooking a standard practice to improve the taste; it's not a motivation, nor a deliberate aim, it just happens as a sort of side effect of the cooking.


    Kanzi can dig fire as far as using it goes, but the bald wizards have to give him a magic wand to make it with. Take away his lighter and he'd be screwed unless he was lucky enough to happen across something that had taken fire from natural causes.

    Technically true but remember that humans didn't get the knack of making fire for many thousands of years after we figured out how to use fire. Kanzi has never had to maintain a fire because of the magic wand; if bonobo tribes where taught fire and then weaned off of lighters we might well see them learning to preserve fires.


    I'd imagine that [axes and saws] are just what they wouldn't invent. Nor would intelligent moles invent spades.

    That's a good point, which is why I went to the more interesting topic of ropes. Clever beavers could use readily made cordage for lots of things, such as the already mentioned baskets. Axes were merely offered as something more immediately relevant to beavers than the spear, which was of interest to meat eating humans who also shared living space with human-eating predators.

    It occurs to me that while beavers are mostly herbivores, some other opportunities present themselves. Clever beavers might not be just larger and smarter but also more flexibly omnivorous; just eating insects (intentionally rather than incidentally) might give them useful protein, and they do most of the work for fish farming already. Imagine a beaver darting through the water with a net in one paw...


    I'd say shovels and nets; beavers have already invented canals as a means of moving larger bits of wood than they can drag, and shovels will make building and maintaining the canals easier.

    Nets not only mean that they can transport more stuff, but that the storage volume of their lodges rises significantly for no extra exterior size.


    Ahem: a pyrogenic species doesn't necessarily have to be a tool-making culture-using species, and vice versa.

    We can hypothesize non-sapient pyrogenics (the earlier example of Vernor Vinge's hypothetical avian scavengers who like their carrion well-cooked springs to mind) and if such a species emerges, a different species without the physical adaptations to easily make fire could conceivably domesticate them.

    How this would work in practice is an open question, of course. But let's not get too hung up on all the necessary adaptations having to come in one handy primate-shaped package, shall we?


    Yes, that's what I was getting at - he knows how to use fire, but the matter of making it is externally-provided magic rather than something he understands for himself. It would be interesting to see if, for instance, if he's only given a lighter once every few days but has plenty of fuel if he figures out how to keep the fire going to compensate, also how well he can transfer his knowledge to other bonobos and what use they make of that knowledge collectively.


    Actually we don't know that at all. We could easily fit a near industrial smart dinosaur civilisation (or two or three) into Earth's past without having any evidence for it today. We assume we're the first, and we're probably the first to make widespread use of nuclear power and plastic but beyond that its an unknown.

    Actually, I don't believe this happened, but there are paths to tool-using civilization that could conceivably bypass fossil fuels entirely and go straight to nuclear!

    For this to be viable, though, you'd need species with an encephalization index capable of going the distance to have emerged when the earth was at least 1.5Gy younger (which is pretty much right out of reach for vertebrates).

    The big tell is the natural fission reactors at Oklo; 235U has a half-life of 700My, and while there's far too little of it in uranium ore for spontaneous criticality to happen in the current epoch, back before a lot of it had decayed all relatively pure uranium ore deposits probably qualified as enriched/reactor-grade uranium by modern standards.

    So the path to tech starts with windmills and water wheels, but then somebody notices those interesting hot springs, or the way the sack of orange pottery glaze gets very hot and sparkles if you let it get wet, and use fission to power low-pressure beam engines -- and that's how they roll.

    Realistically, this isn't plausible for Earth's deep past (1.5-2Gy ago there wasn't enough oxygen in the biosphere to support much if any multicellular life: also, lunar tides would be much harsher -- the moon orbited a lot closer before tidal drag moved it further out), this is an option for the deep future, for late third and fourth-generation star systems during the mid to late stelliferous era: by the fourth generation I'd expect newly formed earthlike planets to have a much higher relative abundance of heavy isotopes.


    It's been a while, but didn't the same book also have someone spending a few tens of thousands of years trying to teach the local monkeys to be sapient tool users?


    It's not clear whether the fact that they flock into the hundreds means they have a very high Dunbar Number, or if they have some social subdivision that we don't see in those flocks.

    Cockatoos flock in the hundreds. One interesting behaviour is that when they move from one location to another during the course of the day, usually the entire flock (300-400) does so but the individual birds, rather than flocking as such fly in small squadrons of at least six up to around a dozen. Experiencing such a group overflying at low altitude, screeching loudly, can be quite confronting - especially when there is a large flock transiting the area. When a group lands to check out the immediately local foraging situation it can be anything from 1 or 2 through to a group of 6-12 and up to 30-40. I don't recall more than that turning up in my backyard at once, even with passion-fruit and mangoes for the taking.

    My local cockatoos live permanently in a stand of tall trees in a golf course, but their foraging radius seems to be single-digit kilometres. They co-habit with large numbers of (native) corellas and (not deliberately introduced but nonetheless invasive) ibis, along with several smaller species. I've seen no evidence of mingling, though only a very low minimum of screechy, squabbly violence over perching sites.

    The required conditions for a culture of cosmopolitanism among these larger bird species would include a few things. A lack of fearfulness or overt territorial aggression toward other groups and species. Curiosity and cultural transmission of information. Lifespan in the decades and evidence of reasoning about a mental model of the world (including a theory of mind, but more broadly an awareness of the world beyond one's experience and immediate consciousness, and one's existence in it).

    Anyway, consider a civilization composed of a massive heterarchy of intelligent birds. What should we call it? Perhaps a polyculture?

    Polly-want-a-cracker-culture? Seriously though, if this already existed (perhaps other than the cross-species mingling) how would we know?


    Really? What about decreased demands on the immune system from cooking eliminating many parasites and diseases?

    I would speculate there would be a strong correlation between life expectancy and cooking.


    Yes. And it's why cephalopods could use tools - no fire and no metals, but that leaves a lot of technologies. On this matter, England had some sort of effective social organisation c. 2,000 B.C., without even any real towns, so a civilisation (in the modern sense) wouldn't need cities, though things would take longer. I can imagine quite a high level of technology that would leave nothing noticeable in the fossil record over a megayear, based on natural materials, biotechnology etc. I am talking late 19th century in mechanical engineering, and well ahead of us in biological. Some SF authors have included such things, but most have been scientifically implausible.

    Aside: flint tools weather to unrecognisability, incidentally, but I don't know the timescales, except that they're condition dependent.


    Like all physical and mental functions, your immune system needs regular exercise :-) More seriously, what I have seen indicates that the big advantage of cooking is the increased digestability and detoxification of plant material, which both increases the range of useful foods and vastly reduces the time needed for gathering and eating. The improved taste is the pleasure that encourages this (standard evolutionary feedback). The parasite issue is almost entirely for meat, pretty minor (there aren't many relevant ones), and negligible compared with boiling water for drinking!


    And if the legend that Jewish/Muslim prohibitions on pork are dressed-up rules for avoiding tapeworms is true, then cooking isn't necessarily even all that effective for eliminating relevant parasites from meat.


    I love that, but there is the problem that when the sack of orange pottery glaze gets wet, whoever spilt the water on it dies horribly not long after. That might put people off a bit. I'm not clear how you'd get round that unless you can postulate a magical immunity to radiation poisoning...


    Well, AIUI most Halal/Kosher dietary laws are pre-refrigeration best food hygiene practice rather than aimed at specific parasites.


    If life arose on a fourth generation planet, you can safely assume that it would have a heavy metal and radiation tolerance much higher than anything on earth, except possibly our most extreme extremophiles. Conversely, it would be unable to survive here, except perhaps in our most toxic waste dumps, because of malnutrition.


    As the species that makes this discovery evolved in an intrinsically higher-background-radiation environment than our own, I'm guessing they may be rather more resistant to ionizing radiation than we are: think D. radiodurans levels of resistance as a baseline for their regular prokaryotic antecedents. (D. radiodurans can withstand an acute dose of 5000 Greys with no loss of viability, and 15,000 Gy with roughly 37% viability; 1 Grey is a roughly LD50 level of radiation exposure for our kind.)


    IMHO this applies with much less force to thorough cooking. While there are some toxins that occasionally turn up in food which are heat-stable, macroscopic parasites such as worms are indeed killed by thorough cooking - and so are bacteria. And for various reasons, the parasites that infest pigs are much more likely to cause us problems.

    There is a reason why many people eat their steak rare (or even raw as in steak tartare) but just about nobody eats rare pork. Incidentally, it might be worth mentioning that the safety of rare beef only extends to solid chunks of meat - not burgers. There have been a number of cases of food poisoning involving burgers cooked rare; the reason is basically that bugs on the outside of a piece of meat are mixed into the centre of a burger. A solid piece of meat won't have bacteria inside it until it's obviously rotten.


    Yes, someone tries to teach "fishermonkeys" Cahokia-style pyramid building with baskets and dirt. And possibly more advanced fishing methods than they are already using.


    Gur Ovt Onq vf fragraprq gb rgreany yvsr jvgubhg grpuabybtl sbe zheqre. Ur riraghnyyl fgnegf genvavat svfure zbaxrlf gb uryc uvz ohvyq n clenzvq. Abg pyrne rknpgyl jul, fvapr ur unf ybat fvapr tbar penml sebz vfbyngvba.


    1 Grey is a roughly LD50 level of radiation exposure for our kind.

    In the Old Guy Units I tend to use, a Gray is 100 rad, and the LD50 is a few times that modulo circumstances. Not that that level of detail is significant in the present context.


    Hmmm. Cats domesticate humans to make cans and can openers? Seriously, though, this is a situation of (social) parasitism on the pyrogenic species. The key question there is, why should the parasite grow a bigger brain? It diverts resources from having more baby parasites.

    There aren’t any venomous predators that hunt large game... Komodo dragons are the extreme case of nonvenomous but highly toxic mouths.

    Komodo dragons have glands in their lower jaw that secrete toxins (including anticoagulants) and ducts that release the toxins between their teeth; it seems the "dirty mouths that cause blood poisoning" hypothesis is outdated.


    On pyrogenesis:

    making sparks is easier with flint and steel (though it still takes a certain amount of practice to get it right) but it also works with two flints. And we know that there have been a lot of flints striking each other for a very long time on this planet... I don't think we need to wait for carpentry for an overlap between tool use and fire production.

    Also, there are cultural traditions where people put out all the fires in a settlement on the first day of the ritual year and then re-lit the household fires from one that was ceremonially kindled (often using percussion or fire drills) by ritual specialists.

    In many traditions letting the fire go out was bad luck (and not just because it was hard to restart). Hence institutions like the Vestal Virgins whose job was to make sure the official fire did not go out until it was supposed to.


    I'm admittedly very rusty, but I thought 1Gy was on the order of 1000 rads?

    Survivable radiation dose varies depending on the type of radiation and on medical support, but you'd know about 100 rads (it's enough to induce symptoms of acute radiation sickness) and ten times that would be fatal without hospital support and serious nursing.


    1 gray = 1 joule per kg. Not adjusted for relative lethality of radiation type.

    They used to give 4Gy as the "Abandon all hope" dose when I studied health physics at uni. Pretty much guaranteed to kill human tissue.

    A couple of people have taken that sort of dose to body parts and lived, generally resulting in amputations.


    I'm admittedly very rusty, but I thought 1Gy was on the order of 1000 rads?

    No, 100. After the unfortunate Fukushima incident I was motivated to find out what sieverts (100 rem) and Grays (100 rad) were.

    The radiation/radioactivity units are not totally easy to keep straight, but not as bad as photometric units, which verge on the bizarre.


    Beavers (the genus Castor) are only ten or twelve million years old; I'm not at all sure they will both survive to 50 megayears but assuming they do they should have some great new tricks. They are a keystone species that already reshapes their environment to suit themselves, incidentally enriching it for many others. That includes salmon, themselves a keystone species in some areas.

    The beaver lifestyle lends itself to gardening; they should be encouraging useful plants. They already do this to a degree. Perhaps clever beavers could create thorny hedges as territory markers and to deter predators?

    One thing real beavers don't have that would be handy is any meaningful earth moving system. They use mud a lot in building dams but they don't dig canals worth a damn. Even crude ditches would be handy and once you've made that breakthrough you're halfway to irrigation canals, artificial ponds, and log flumes. I'd expect clever beavers to become really good at managing moving water.

    Currently beavers don't regularly congregate in groups of more than about ten, and while they recognize their neighbors they don't mingle very well. I fret that any hypothetical clever beavers might have low Dunbar numbers, which would pose an obstacle for building larger societies. But beavers are already far ahead of our ancestors in building and in letting other species hang around their homes, so it's not unthinkable that clever beavers could just take a little longer than we did to work out social structures surpassing that limit.

    I'm finding the 'stone age beaver' concept to be novel and entertaining to think about. Are others interested – or fed up with the beaver thing?


    When the FB nuts post their memes about Fukushima poisoning the oceans and everything is dying because of it, explain it in Banana Equivalent Dose to the retards.


    One thing everyone seems to have missed on coal, and other items, oil, metals, etc, is that over the last 40 years or so (re the "War on Coal" bs), mining companies have moved to surface/mountaintop removal, and use giant shovels to get it out; other mining is similar.

    The upshot of this is the same as the industrialization of farming. I've read that harvesters lose 20% of the crop, and gleaners will go in and come out with plenty. The same's true of mining - if the vein isn't big enough/pure enough, it's not "economically viable".

    The upshot is there would still be a lot for startup of fire-based energy production.


    "And we know that there have been a lot of flints striking each other for a very long time on this planet... I don't think we need to wait for carpentry for an overlap between tool use and fire production."

    Thank you. I agree, and I'm glad somebody got the point :)


    Re post 225, I don't give a rat's ass, I'll keep defaming them. From the damn ones that would get into our garden, when we lived in Chicago, and take one bite of a green tomato, nope, this doesn't taste good, and go on to the next, and the next.... To... close friends gave my late wife and me a hybrid apple tree. The year after she died was the first time it gave apples... AND THE GODDAMNED TREE RATS TOOK EVERY ONE. I was ready to wrap the tree in wire, and plug it into house current, and fry the buggers.

    Screw squirrels (ok, except for Rocky).



    How well does that degree of radiation resistance scale to more complex organisms? We know that it can arise in simple eukaryotes because there's that fungus in the ruins of Chernobyl that eats gammas, but is it compatible with the complexity of a brain and its support structures? Or would we be more in the area of cold-climate termites with fission-heated mounds? (I have no idea, I'm just wondering.)


    I like the idea, but not knowing much about beavers, I find myself reminded of another aquatic mammal that constructs concealed dens with underwater entrances: otters. They are already both highly intelligent and remarkably dextrous, with an understanding of basic mechanics and hydraulics and a good problem-solving ability both mentally and physically. (Can learn to turn taps on to play with the water, for instance.) Remove the human pressures on their habitat and see what happens?


    Any solid reflective surface that can be easily positioned (angled to reflect/focus the sun) could be used to start a fire. No idea whether anyone has ever tried to start a fire using naturally occurring crystals - salt (NaCl), quartz, etc. - as a lens or reflective surface.

    Decided to look up degradability of various shiny substances: - Aluminum cans/foil take 80-200 years to decompose. - Glass bottles - 1 million years - Gold lasts forever as it doesn't tarnish, is soft and very reflective so could be the first metal used to start a fire. (Couldn't find how long stainless steel & copper metal pots & pans last.) - Plastic bags - 500 years to forever according to the link below! So all of our Baggies, Ziplock, Saran and clear plastic produce bags might be the most important tech that humans leave behind for the next fire-making sapient. (I've cooked food in a Baggie immersed in hot water - no problem. In fact, this technique is becoming quite fashionable as 'sous vide' cooking.) More importantly though, water/ice in a clear plastic bag can be used as a lens to start a fire.

    These are the no-fire-needed food-prep-as-a-means-of-outsourcing-some-digestion processes I'm aware of: curing/air drying, salt/sugar, burying in ice/ground, and pickling (just add any acidic juice). There are probably more, so please feel free to add to the list.


    tardigrades are looking more interesting.

    Seriously, I suspect that there are more radiation resistant critters out there than fungi that "eat gammas" (which isn't how fungi work)>. The article referenced above is quite interesting, because that particular tardigrade became more stress tolerant both through acquiring novel proteins and disabling metabolic pathways that exist in other organisms. Radiation resistance isn't simple.


    Keep it up. I'm quite fond of beavers too, both real ones and as templates for aliens. The interesting part is that you can actually do some fairly sophisticated wetlands agriculture by making mounds and ditches, and what beavers do with their dams is extremely useful as well.

    When thinking about aliens, beavers are high up there as models for aliens that intelligent in a way that's both different from humans and understandable nonetheless.


    First round candidate eliminations In the spirit of this, perhaps we're ignoring (due to ignorance) what sorts of minds might become technological civilization creators. I'm thinking that at least some members of a community would need to be able to maintain mental models of the spatial relationships between members of their community, and between the community and threats to it and resources that it can use. This is the sort of model that an elephant matriarch maintains. She's tall, eyes wide-set (3D), and so can build a pretty good mid-range model visually (especially in a savanna.), and tie it to memorized models of other areas in a much larger patchwork with directional relationships between the patches. (Plus some temporal memories, to handle seasonal changes.) I'm making presumptions about elephants here without direct knowledge though have watched matriarch-led herds in the wild (on a wildlife safari). Alas, no hands. The high wide-set eyes approach could be perhaps substituted for by having a subpopulation that serves part or full time as mobile scouts and builds spatial models with movement of view-points plus short term memory.

    Communication of these models would also be a winner; the matriarch elephant keeps the model in her head and presumably (would be interesting to be wrong) does not share it. It dies with her, and a second picks up the role, perhaps poorly. Some non-human animals transmit some important information culturally, notoriously some corvids. (Tried to find a UK person doing this sort of work; this will have to do) Every so often Marzluff’s group retests the birds. It’s been 10 years, and not only have the crows not forgotten, the knowledge keeps spreading. When a crow sees other birds mobbing, it joins in, learning and remembering the identity of the villain. Each time, more birds mob and scold. Nearly all of the birds originally trapped by the caveman are likely dead by now, yet the legend of Seattle’s Great Crow Satan still grows.

    The point being that there may be important features of social organisms that we're ignoring because there's no theory of evolution-to-technological-civilization-capable-state. We have a single existence proof, and should work through all the unique/semi-unique characteristics of Homo Sapiens, discarding them only when thoroughly convinced that they are not a key part of the path, that would need something similar or a substitute.


    OT, to Troutwaxer, if you are lurking, I worked up a speculative answer to your "CTHULHU / WEB 2.0 APOCALYPSE, 2016" question in the Writer, Interrupted thread. Noticed a temporal relationship. You might be amused.


    There's another key point that seems to have gotten missed. Intelligence is a wide spectrum of traits. While I don't know if elephants are better at spatial mental maps than are humans, they're at least as good, and due to their use of odor and infrasound for communication, almost everyone (outside a few specialists) is probably unaware of just how social they are and how much they communicate.

    There are similar stories for any cultural animal species, from coyotes to beavers to chimps. Again, intelligence is a massively multidimensional space, not a scale, and humans occupy a fairly small part of it. If we're starting to talk about a species that does technology as humans do, then we need to invoke the whole evolutionary story of fire. If we get away from that, there's still a lot of different kinds of intelligence and culture.


    but you'd know about 100 rads (it's enough to induce symptoms of acute radiation sickness)

    Yes, just going on old memory, at 40-50 rem it's detectable in the lab, 100-200 you're getting noticeably sick, 400 very sick/might well die (LD50), 600 rem basically everybody dies in a few months at most. 10,000 rem pretty much disables/kills you on the spot. Qualifiers apply, such as kind of radiation and medical care, but that's the general picture.

    Lessee.. Yes, here:


    They seem to be actually using the energy of gammas to enhance growth, which has got to be pretty cool.


    One thought re. beavers or other (otter?) damn builders: Fastest growing higher plant is duckweed (allegedly can double it's mass every 5 days under good conditions), Some algae apparantly grow even faster. So a large, calm water surface with plenty nutrients could maybe feed more animals than the same surface as forest or grassland. AFAIK this is not what we see in terraforming animals now, but it does not seem impossible.

    This is what I was thinking about re. water holes upthread - if animals creat water holes (where surface runoff can gather), they could create ponds in otherwise dry areas. If they build their holes along slopes of hills, and instinctlvy follow contour lines, your half way to a rice paddy ...

    A thought re. fire or rather no fire: Let's go with the idea that the main use of fire is as an external pre-digestion, allowing a smaller GI tract. What other ways are there to pre-digest food before eating? crocoiles deposit their kills and let the meat rot a bit so it's softer. Not the same. Crocodiles (among others) also delegate the hard part of digesting fiber to gnu andother herbivores. Old hat.

    Possibly new hat: Acidic fermentation (kimchi, sauerkraut, silage, ...) is done to make food keep, not to make it more digestible. But it could have the effect anyway, when the fiber partially breaks down under tha acidic conditions. There's probably research out there re. how good cattle handle grass silage vs. fresh grass, could be a start. Anectotally, I heard one guy who mostly eats probiotic stuff that since then his food passes him in shorter time. Ensialging needs anaerobic conditions and a bacterial starter culture, which an animal that eats like this probably can provide by spitting. An animal doing this would not need to carry such a large gut around. I think the other metabolic costs of digesting (generating acid/enzymes) would be the same and there would be little or no extra calories from the food.


    Late to the thread, but I once theorized a humanity that had not only culture and genes, but also parasite lineages as a way of inheritance and relied on cannibalism to get there (tl;dr: we evolve symbionts, then implant them. We're also quite protective of the good ones, with all sorts of social consequences). Having three ways of inheritance at work would make it even more screwy than the current interplay between culture and genes. And I see nothing that would prevent it from working with other species, are there any ants with a wide array of symbiotes?


    Beavers again: I'm thinking about predation; that appears to be the biggest thing beavers have to worry about and their biggest driver to develop intelligence. They master other aspects of their environment pretty well but they're still conveniently sized meat meals. Wolverines, foxes, wolves and other midrange carnivores are all too interested in beavers. (Bears apparently only eat beavers occasionally, and while alligators are aquatic predators their range overlap is minimal.) Honestly, I'm not sure where to start with early stone age technologies and clever beavers. Snares would be straightforward but how does a trapper keep other animals from triggering them? Or if manually triggered, how is the victim lured into place? Deadfall traps pose the same questions. Even with a pointy stick the clever beaver versus wolverine match does not favor our tool makers. Fences to deter wandering carnivores? Tribal counterstrike expeditions against predators such as wolves that are smart enough to be deterred? I'd expect a wave of carnivore extinctions when some clever beaver works out the bow and arrow!

    Potential symbionts and domesticates will be interesting, since there are so many species already found near beavers. Many fish thrive in beaver ponds, including trout and salmon species; clever and omnivorous beavers might actively encourage them. Otters and mink are often hanging around but may not particularly help or harm beavers; otters are certainly clever – maybe clever beavers could try to make them companions as we've adopted dogs? I've already guessed that they'd cultivate plants that yield raw materials for cordage. I'm not sure yet what birds might help them, and while termites should love beavers it's not clear why beavers would love termites.

    They won't get sophisticated ceramics until they master fire, and beavers seem to need that less urgently than our primate ancestors did. They'll go fucking nuts with it when they invent concrete.

    Regarding real beavers, they react to seeing water go over the top of their dams but are pretty casual about water level in the abstract, which is why the pipe trick works more often than it doesn't. (A backhoe is not the trump card you'd imagine.) Beavers are industrious and resourceful when dealing with problems they understand so it's a good idea not to show them anything they recognize as a problem.

    That leads to a story that reflects poorly on their adaptability. Beavers are known to respond to the sound of rushing water, hurrying over to new holes in their dam to patch the breech with sticks and mud. A scientist with nothing better to do recorded this sound and then played it back in the middle of a field; beavers rushed over and covered the noisy tape recorder with branches and mud, even though it was on dry land meters away from any water. As for me I'm not writing off beavers, because I've seen my fellow humans do things much dumber than trying to bury a tape recorder.


    A belated note about fire: Particularly in the high-oxygen scenario Charlie posited, you don't actually need to be able to create fire yourself. All you need to do is find a way to preserve, propagate, and transport an existing fire, as seen in "Quest for Fire". The whole notion of the priesthood of the fire in that movie was mostly played for laughs, but it's actually quite plausible as a mechanism.

    Forget where I saw it, but some SF/F author has written about aquatic creatures using the equivalent of vacuum suits and safe rooms to manipulate fires burning in the oxygen atmosphere and use them for scientific research, smelting, etc. etc. Also struck me as very plausible.


    There's sort of a simplified over-generalization that plants that grow fast don't live long. Duckweed's a tiny little floating plant, and once it's covered the surface of the water, it starts competing with itself. In this regard, it's no different than other floating water plants. So far as I know, each plant doesn't live very long.

    While it is eaten (by ducks and others), its nutritional value is somewhere around that of lettuce, since it's basically a tiny little leaf, getting its minerals out of the water immediately surrounding it.

    Another thing is that fiber doesn't break down all that well under acidic conditions. Otherwise bogs (which are very acid) wouldn't exist, nor would coal (the fossilized remnants of marshes). Anaerobic conditions, as you noted, inhibit respiration, which helps kill a lot of aerobic microbes that cause decay and/or disease. As animals found out a long time ago, the simplest way to utilize fermentation is to modify your GI tract to accommodate it better. That requires evolution more than intelligence, but it turns out that fire is way to get around this, if you happen to have a big supply of wood or other fuel to feed the fire.*

    *You can think of campfires as a human way of metabolizing wood, if you've got a weird turn of mind.


    ...are there any ants with a wide array of symbiotes?

    Rather than going on a link rampage I'll just say yes. There are a lot of... no, that's not right. There's a fuck ton of ant symbionts, parasites, predators, mutualists, and associated hangers-on. Ants are everywhere and have been around for 100,000,000 years or so. Ant associated species are everywhere!


    But specifically, a single ant species with a wide array of symbionts? Not just ants in general?

    Also it just occurred to me that we may see something similar to my idea with the parasite lineages once we figure out our gut flora and start manipulating it on purpose. No cannibalism needed.


    But specifically, a single ant species with a wide array of symbionts?

    Oh! I understand now. That's a good question. I want to say yes but that would just be a guess; I don't find any specific examples offhand. My google-fu is weak today and the number of ant symbionts is large.


    The highest number of symbionts I know from a single ant species is from the invasive argentine ant (Linepithema humile), which seems to tend a wide variety of aphids, both native and non-native, some of which are ant specialists, some of which are not.

    Normally, in the myrmecological literature I've read (which is heavily slanted towards EO Wilson, and not the primary articles), there seems to be a bias that each ant species has a few symbionts, ranging from mutualists to parasites. In this regard, each species has many fewer symbionts than do humans, and this includes argentine ants. However, argentine ants seem to have a real knack for working with local aphids they didn't coevolve with, something my landscaping friends have noticed because it results in so many dead plants. This makes me wonder whether other ants are similarly promiscuous/adventurous, and we simply haven't noticed.

    Regardless of argentine ants, humans probably have more than a order of magnitude more symbionts (domestic species, pests, etc.) than does any ant. This is another way in which humans really distinguish themselves from other animals. We're up there past big trees like oaks and tropical figs in terms of the number of things that live in, on, or with us.


    Thanks for this! Good to know that most mammals are flexible re: diet.

    Re: Your pasta eating cat ... and other stuff that pets eat

    Our cat found potato chips (crisps) irresistible. No idea how that started - probably a stray chip landed on the floor near her food mat at some point while we were still eating chips or had the bag open. Even though we didn't actually ever give her chips, she'd sidle up to try and lick our hands/fingers whenever we had any chips going. Odd thing to tell guests: keep your eyes on your chips because the cat's going to eat/steal them.

    One of our dogs used to steal the baby's milk bottle right out of her hands/mouth; he just rolled on his back and sucked it back. He didn't try this with juice - just milk.* Same critter was also apprehended once on the kitchen counter trying to sink his teeth into a cello-wrapped still-frozen roast.

    (* Yes, we put a stop to this by sending this dog outside any time the baby had a bottle.)


    My mom's old cat was rescued as a kitten from a recycling facility, where she'd survived by begging scraps from the workers. To the end of her life, she liked bread (especially tortillas), melons, peas, yogurt, milk, and ice cream. I suspect she was lactose tolerant. I've seen other cats that liked things like scones, so cats eating baked goods is definitely a thing. I suspect that added butter and salt make some baked goods more acceptable than others.


    One driving question for me is about how a capacity for abstract thought evolves. I was going with models (in particular spatial models) because a basic model is pretty much 1-for-1 with perceived reality, but if a model could be simplified, or reused (or at least the modeling apparatus re-purposed) in other contexts (e.g. social contexts), or extended to improve the accuracy of predictions that it facilitates, or ..., then the utility of such abstract thought would drive its perhaps-rapid evolution. Or something like that.

    So general question to readers here; where is the literature on these sorts of questions? Poking around a very little, I was finding surprisingly unexplanatory stuff like what's in the the wikipedia article (which is worth a skim for the background).

    This also potentially interacts with Theory of Mind (for those that prefer less erudition, wikipedia), which CT (et al) has often asked us to think about. Models of the minds of others are models, which potentially can be manipulated and re-purposed as well. A model of the mind of (a member of) one gazelle species is perhaps a good basis for a model of the mind of (a member of) another gazelle species.


    I'm not sure space maps 1:1 among all people. Compare how archaeologists and botanists see landscape. Archaeologists are trained to strip off the vegetation to look for human artifacts, botanists are trained to ignore the artifacts and see the plants. As a result, archaeologists and botanists have to cross train for quite a while to see each others' realities, even when they work together.

    These are two human examples. I suspect that if you look at how dolphins map the ocean with how chimps map a forest and elephants map a desert. They're all perceiving the world in different ways. Are they comparable?


    Somewhere between #232 and you #269 that I'm replying to, I suggest that a game changing tool for beavers would be the shovel, for exact the reason(s) that it makes canal building (and hence irrigation), and possibly dam building/waterproofing, easier. And yes this does mean that I'm interested in a possible "beaver uplift scenario".


    Otters are also known to be another tool-using species, in particular holding stones and using them to break shellfish open.


    AFAIK its not uncommon (in fact it may be a majority state) for felus domesticus to be lactose intolerant.


    And some people are quite simply "better at navigation" than others. You may know someone who needs a street address and a set of detailed directions to find your place? OTOH if you told me "get onto Main Street going West, go 2 miles and turn left onto Rosalind Franklin Road, and I'm at #703" that would be adequate for a first visit going out from downtown, and next time I'd be able to get there off the freeway heading in-town from a different street.


    AFAIK its not uncommon (in fact it may be a majority state) for felus domesticus to be lactose intolerant.

    My understanding is that most adult mammals are lactose intolerant. There's little point in most mammals continuing to invest in the biochemical pathways required to digest milk when the chances of getting it once weaned are close as dammit to zero. Cattle farming humans being the exception.

    It's not that cats can't get some benefit from the fats in milk, but the lactose will usually give them the squitters. Cream, with both a higher fat content and a lower lactose content than straight milk, may be a bit less problematic for them.

    (Quite why mammalian evolution settled on the lactose/lactase combination is an interesting question. Why generate a sugar that requires a specialised enzyme to make use of?)


    (Quite why mammalian evolution settled on the lactose/lactase combination is an interesting question. Why generate a sugar that requires a specialised enzyme to make use of?)

    Your nipples (and baby) don't get opportunistic yeast infections if you use lactose. Use glucose or fructose instead and all sorts of unpleasant microbial free-riders will chow down on baby's meal.


    Cats need to outwit (or maybe just be one step ahead of) humans because humans tend to try to limit their numbers by spaying or neutering potential breeders. Unlike dogs (humans intentionally selecting interesting or useful variants and breeding from them) most cats who reproduce do so in spite of rather than because of humans.

    In western countries around 80% of the cat population have been neutered so that's pretty hefty selection pressure to reproduce very young (before human gets round to organising neutering) or escape from confinement (where human is trying to prevent reproduction by keeping the sexes separate) or to select a human host who's too dim to organise neutering at all.


    Feral cats have been observed drinking milk from northern elephant seals (which doesn't contain lactose presumably because marine mammals have less of a microbe-contamination problem).

    I think they might have some difficulty cultivating seals as a human replacement, though.


    They both like fish, the cats can ride on the backs of seals to get to islands and they can bat the noses of any orcas that decide to have a go.

    Sounds idea.


    Also, that lactating mammals produce milk with specific enzymes that promote growth and development for their given species … cows milk is for calves and human milk is for human babies. Breastfeeding of human babies is critical in the first six months to a year for brain development.


    Thankfully these enzymes aren't overly species-specific. List of animals whose milk humans have been safely consuming for thousands of years:

    Cows - West Water Buffalo - India Goat - Wherever goats are found Reindeer - Lapland (northern Scandinavia) Horse - Mongolia, Russia Sheep - Wherever sheep are found Camel - deserts Yak - Tibet

    Personally I think (i.e., no science data supporting this) that apart from sheep and goats which often need to be milked twice a day, the key reason these mammals are preferred milk sources is their size/volume of milk produced. If this is so, then in a pinch, it might be possible to farm/raise other, smaller mammals as dairy animals.


    Can you say "exponential growth"? Because that's what you get with a healthy female cat producing 2 or 3 clowders of 4 to 6 kittens twice a year.


    And all the cats have to do in return is learn to hold their breath for 5 minutes! (or be Turkish Vans, which enjoy swimming).


    I don't know a lot about the others, but I have to take exception to Horse.

    It's been well known as a powerful laxative for thousands of years, so it has been safely drunk /after fermentation/.

    I don't know how to describe koumiss* but it bears as much resemblence to milk as beer does to wort and wine to grape juice.

    Other than "vile", but that's just my uneducated western tastes showing.


    That's why it was so weird for this cat to continue eating dairy products into old age.

    I've got two guesses for cats that like lactose. One is that cat kibble is reportedly designed for the pleasure of the owners, meaning it's aimed at producing dry, non-smelly stools. If lactose acts as a laxative, the cat may figure this out and deliberately eat it to have a more comfortable GI experience.

    Another possibility is that cats have haunted European barns for centuries, and it's a standard trope that some will beg milk from whoever's milking the cows. In such an environment, I'd guess it's possible that some cats became lactose tolerant. All lactose tolerance requires is the continued production of an enzyme into adulthood, rather than shutting it down. Several such mutations have cropped up in humans, and I can't think of a reason why analogous mutations wouldn't show up in farm cats and get passed along.


    Okay, I'll go for that: Nature's version of DRM


    In the spirit of the Cthuluphant and to vary from the beaver thing for a while, here are some other things we might see. I have a nagging suspicion none of them are nearly different enough for a 50 million year gap; they might show up in five or ten million years.

    Boomboo: It's not clear when pyrotic insects first took shelter in bamboo groves but certain caterpillars are common parasites that eat the pulp of live stalks. When the season is right the stalk dies and its internal walls become highly flammable; the base gives out chemicals normally associated with a good meal and hungry caterpillars will come – only to fall into the lethal trap set for them. In a fraction of a second their anti-predator suicide gland goes off, the fuel layer catches, and a high pressure shock wave blasts upwards through the interior of the stalk, launching the seed pod high into the air to spread seeds far and wide. The stalk itself shatters into a cloud of flying debris but that's fine as the seed pod is by then flying off into the sky.

    Hive Sloths: These shaggy giants slowly move through the forests eating leaves and such other vegetation as presents itself. Appearing to be covered in matted green fur, closer examination shows that they're not really dreadlocks but cleverly woven living space for the ants within, maximizing surface area for the algae and fungus that grows there. They can easily be mistaken for piles of vegetable rubbish when curled up motionless. Hive Sloths will follow specially laid ant pheromone trails to food or sloths of the opposite sex.

    Sea Rock Turtles: While the medieval European fantasy of turtles the size of islands was fanciful, sea turtles can grow quite large. Ranging between ten and twenty meters long as adults, several species of turtle swim slowly but steadily and feed on plankton, rarely diving beneath the surface. This makes them attractive to sea birds, who enjoy having a place to rest; in turn their shells become covered in guano and it's a rare adult that doesn't have at least some plants growing on top of it. The feedback cycle of birds, plants, insects, fish, and more birds can continue indefinitely and older turtles can have diverse ecosystems on their backs. This feature is why, in the long term, they can pose a threat to established ecologies along the shoreline, since as they migrate around the ocean almost any small local creature could hitch a ride and end up someplace that is not prepared to handle it. They can reach great ages but are most vulnerable during egg laying, when the female will find a promising tidal flat and allow herself to be stranded by the outgoing tide. During the hours she is depositing her eggs she is also immobile and vulnerable.

    Pond Otters: As the ancient humans kept house cats, so many clever beavers keep pond otters. For ages otters have been cohabitating with beavers, catching annoying pests, and making messes in the house. Pond otters have evolved to look more juvenile and display behaviors that the beavers find amusing; they spend much more time than their wild cousins playing, snuggling, and sleeping in the sun; some have been trained to do tricks. While their little paws are dexterous for animals they rarely have the attention spans to accomplish large projects; many otter owners have been thankful for this.


    the fuel layer catches, and a high pressure shock wave blasts upwards through the interior of the stalk, launching the seed pod high into the air to spread seeds far and wide. The stalk itself shatters into a cloud of flying debris but that's fine as the seed pod is by then flying off into the sky.

    Niven again:


    Re: 'Sea Rock Turtles' - Pratchett & Baxter have a creature like this (complete with its own ecosystem) in their The Long Earth series.


    Boomboo: Funny, laughed. Seed dispersal is one area where evolution really shines at coming up with interesting techniques. At random, first amusing 'splody one found: Hura crepitans: The fruit is a large capsule with explosive dehiscence; seeds can be launched at 70 metres per second (160 mph).[4] One source states that ripe pods catapult the seeds as far as 100 metres (330 ft).[5] Another source states that seeds are thrown as far as 45 metres (148 ft) from the tree, with a mode at about 30 metres (98 ft).[3] It has also been known as the Dynamite tree, so named for the explosive sound of the ripe fruit as it splits into segments. (bold mine)


    Well, if you want to start with the basics,

    Here's one map of the world at +50 million years, assuming plate motions continue as now:

    Here's another:

    There are some amusing challenges: one is that most of the continental mass congregates in the northern hemisphere, although not enough to form the next blobular Pangaea. That's still in the future. This, combined with Antarctica still partially on the South Pole and the lack of a circumtropical ocean makes me guess that Earth in 50 million years might still be stuck in an ice house. This is unusual, in that 80% of the last 500 million years or so has been hothouse, but then again, Earth spent even longer frozen solid, back in deep time.

    However, it still will be a Pangaea of a sort, as there may well be continental connections from Eurasia to Africa to Australia to North America and just possibly South America. This is a spidery, spread-out supercontinent, so there likely won't be a Great Red Desert in its heart, as there was during the last Pangaea. That, too, is in the far future.

    If the Pacific continues to shrink, there will continue to be a ring of fire around the basin, due to subduction and the resulting mountains. The Himalayas will get ground down after India stops moving relative to Asia. On the other hand, the African Rift Valley should spall off an island continent of Eastern Africa, much as it did with India and Madagascar back in the day. Perhaps East Africa will traverse north and collide with Eurasia, sparking yet another round of mountain building.

    So, fewer tropical rain forests, more steppe, and probably some nice big crunchy ice sheets. To me, this tends to favor the kinds of animals and plants we've seen in the last few million years: adaptable migrants, and probably quite a few of them will be smart, if not to human scale intelligence. That's not an argument for stasis in our flora and fauna, merely thinking about the kinds of selective pressures an unstable climate will bring.


    Past 300 so a minor link digression; odds of CME-caused disruptions continue to decline: Regional solar storm forecasts set to begin ...a new geospace forecast model that can give unique data for each 350-square-mile plot of Earth. The University of Michigan model that will be used won a 5-way model-off a few years ago.


    So, fewer tropical rain forests, more steppe, and probably some nice big crunchy ice sheets. To me, this tends to favor the kinds of animals and plants we've seen in the last few million years: adaptable migrants, and probably quite a few of them will be smart, if not to human scale intelligence. Very good point about migration. Glaciation cycles are probably more forcing of species migration than anything else likely, yes? The speed for range shifts (at higher latitude edge of range) is on the order of single/low-double-digits kilometers per decade typically?


    Well, that depends on who you believe. If you believe Richard Alley (Two Mile Time Machine), the switch between glacials and interglacials is quite abrupt, on the order of years. This is where you get into the whole mess of Dansgaard-Oeschger events and rapid temperature fluctuations during ice ages, something not covered in that XKCD cartoon.

    The rough answer is that we don't know how fast things moved, but the guess is that plants and animals somehow survived changes of 3-5oC over the course of years to maybe a century. How they did it is a bit of a mystery, but there's some decent evidence that they did, both in the genes of living species and in the mysterious lack of a mass extinction during the first ice age. My guess is that in the absence of a global civilization blocking every path, migration's a lot easier than we think. Another possibility is that most stuff died, a few hung on in refugia, and then the survivors repopulated the landscape rather explosively as soon as conditions stabilized. That's another kind of migration.


    Just for fun - note tongue in cheek:

    This comes about because someone has an ... unexpected ... success in uplifting cats with opposable claws and tells them that being a humanitarian is a good thing.

    They run out of their new favourite food on December 31st and the post-human fun begins...



    Another possibility is that most stuff died, a few hung on in refugia, and then the survivors repopulated the landscape rather explosively as soon as conditions stabilized.

    Mountains are a form of such refugia that can handle temperature decreases, and minor increases. Elevation is similar to latitude but the horizontal distances involved are small. Is there a vocabulary for types of refugia? (basic link for the interested.)

    Re mental maps, I stumbled across Cartographic Compression, an entertaining read, with plenty of pithy quotable sentences. (Doesn't seem to have been linked at this site.) Random sample: An example of an anticartographic domain is the classic gambling casino. Casinos exhibit extreme local self-similarity, and similarity to each other. They are dark. Their carpets and layouts are confusing; all the paths look the same. Classically, they have no clocks, and if they have windows, they are tinted to reduce time cues.

    From it, a link for Greg: F*&% Nuance


    Elevation is similar to latitude but the horizontal distances involved are small.

    Why, yes. From my home territory:

    Models analyzing how Southwestern plant communities will respond to climate change predict that increases in temperature will lead to upward elevational shifts of montane species. We tested this hypothesis by reexamining Robert Whittaker's 1963 plant transect in the Santa Catalina Mountains of southern Arizona, finding that this process is already well underway. Our survey, five decades after Whittaker's, reveals large changes in the elevational ranges of common montane plants, while mean annual rainfall has decreased over the past 20 years, and mean annual temperatures increased 0.25°C/decade from 1949 to 2011 in the Tucson Basin.


    Anonemouse, re. Komodo dragons having venom glands:

    Kewl! Thanks for updating my map of reality. Some days I think most science journals should be renamed "Journal of Stuff [name of profession] Thought Was True Yesterday -- But No Longer Do".

    On the other hand, that's the fun part of science, isn't it? Each new discovery reveals a deeper Matrioshka layer of reality. Mind blowing!


    Hura crepitans: The fruit is a large capsule with explosive dehiscence; seeds can be launched at 70 metres per second (160 mph).

    Yikes! I think I'll stay out of the garden, thanks. I hadn't known about that.

    Yea, verily, there is nothing new under the sun. The living island goes back centuries, of course. Boomboo was thought up in part because Larry Niven already did the rocket tree idea and I wanted something different; using bamboo tubes as gun barrels, while done occasionally by humans, seemed unlikely to evolve on its own.

    I still like the idea of social insects with external memories, as an abstract concept, but it's hard to imagine what they'd do with that power. It's like trying to envision a termite mound when you've never actually seen any social insects.


    Yes, mountains make great refugia. So do big canyons.

    In the southwestern US, the Grand Canyon is thought to be one of the major refugia. Unfortunately for this scenario, the dams along the Colorado River fail within 100-500 years, and depending on how they fail, they'll send a scouring wall of water hundreds of feet high through the canyon, which will make it less of a refugium than it was in the past. There are certainly similar problems elsewhere through the West, do to our beaver-ish obsession with building huge dams over the last century. Absent maintenance, none of them will last forever, and when they fail, they'll cause immense scour downstream. Kinda sucks, but that's the post-technological future, whether humans survive or not.


    Vaguely like that would be the calibans in CJ Cherryh's 40,000 in Gehenna. They are giant lizards* rather than insects, but they have a multispecies society that uses earthworks and tunnel patterns to store information and/or communicate.

    Then Union abandons 40,000 brainwashed human clones on the planet because they want to stick the Alliance with a third-world hellhole, but I digress.

    • Technically not really lizards because they are from an extraterrestrial ecology, but close enough.

    [Collapsing dams will] send a scouring wall of water hundreds of feet high through the canyon, which will make it less of a refugium than it was in the past.

    Yeah, that can be pretty dramatic. An unstoppable super-tsunami in a closed canyon isn't something you'd like to see up close. Ten cubic kilometers of water an hour coming through a canyon at highway speeds leaves a mark; the energy release per flood is guessed, with wide error bars, at 4,500 megatons delivered as kinetic energy.

    But that was the Columbia Gorge (and eastern Washington. And parts of Idaho, and Oregon, and ...). The Grand Canyon is a bigger and older canyon but also narrower. Hoover Dam normally holds about 1% as much water as Lake Missoula (~20km3 vs ~~2100km3), so a catastrophic failure won't actually flood entire regions at once; it would certainly be a bad place to be standing at the time.

    If given a century or two to recover between the flood and the climate change I think the canyon should be okay as a refugium.


    Beavers again: now that OGH has started another thread this will start dying and I might as well dump what notes I have before it closes down.

    I've addressed plausible early technology routes for clever beavers... but what about their societies and cultures? Beavers are territorial and may not mix bands as easily as we did. However the current ones seem to negotiate borders fairly well and settled adults don't squabble too much.

    Drama occurs when juveniles show up looking for their own places. We may think human teenagers are annoying but they've got nothing on adolescent beavers. Clever beaver society must do something with all this adventurousness and many societies will probably come up with some kind of Youth Usefulness Corps. I've already mentioned using not-yet-settled citizens as mail carriers and cargo haulers; they can also be pointed at whatever projects need large teams of workers.

    Some tribes might pose coming of age challenges. For example, to get an established dam a youth might have to slay a carnivore and come back with its pelt. This is a win-win for the society, as it removes either a beaver eating monster or an annoying teenager; might be hard on the kid, though.

    Art is a big deal for us and presumably will be for many sapient mammals. Clever beavers will probably be better sculptors than we were. Decorative pigments are available in abundance. Beavers are very aware of sounds and clever beavers will certainly invent many musical instruments, doubtless including a huge range of percussion and wind instruments. The extent of singing depends on their vocal development.

    Agriculture no doubt starts as forest management. Nomadic hunter/gatherer lifestyles are less likely, as a rule, but such groups could help bind together extended societies.

    Maintaining communication will be challenging at some stages. I'm imagining literacy starting with visual or physical name tags rather than as accounting records (as the Fertile Crescent cities seem to have done). These marks may well start as physical addresses rather than names; that's not nearly as important as getting the idea of storing abstract information in objects rather than in someone's head. It's not a trivial leap from physical address quipu to full writing but history suggests that people will invent writing when the need arises.

    Even after they have well developed mail service communities will have some way to make loud noises. I won't guess how they'll encode their information but even now beavers signal each other by slapping water; clever beavers won't be less capable. Expect this to overlap with musical instruments as mentioned above.

    If clever beavers have something like the Puget Sound region it may well become their Fertile Crescent or Mediterranean, a rich and hospitable cradle for their transition from the stone age to early civilization. The current Puget Sound is too ephemeral, as well as being full of verbal monkeys, but is otherwise a sheltered body of water surrounded by vast wet forests full of streams, trees, and other resources. It would be a great place for clever beavers to start building a civilization.


    Like all generalisations, it seems that there are exceptions. There is a vodka made from milk — more specifically, from the whey left from cheese making. It's named Black Cow, it comes from Dorset, and they've found a yeast that does work on milk sugars.

    The result is rather nice, enough so that I now have a bottle.

    Amusingly the bottle has a gold top to it. Perhaps sensibly, they haven't made its shape the same as that of a traditional milk bottle.


    Well, dam failure can get ugly. If we assume (and I'll use the Hot Earth Dreams model because it's known) that GHG emissions are something like business as usual and civilization collapses around 2100, then the dams fail during the continued warm-up or at peak heat, so when the canyons are most needed as refugia. On the other side, the dams are likely to entirely stop water running downstream of them. The Colorado will be a lot lower than present, for example, and it might just evaporate in reservoirs, so the river bed may be dry for most or all of the year south of Lake Mead. That makes it a worse refugium.

    It's hard to predict how these two will interact, but if there's any flow in the river, a place like the Grand Canyon will be a refugium until one of the dams give way, at which point it will only remain a refugium for whatever survives the flood, either by being high enough up the wall or incredibly lucky. Some version of that plays out for most of the dammed rivers.

    For Charlie's scenario of death by Christmas and the Earth farts thereafter, it's basically the same problem.


    Minor nitpick about duckweed - protein content is pretty high, % dry weight acording to the first source I found. True, duckweed gets it's nutirents from surrounding waters but those tend to be pretty nutrient rich/heavily polluted.


    A few other thoughts as this thread winds down: Dogs. Dogs where bread for all kinds of qualities (small size! big size! frineldy! mean! smart! cute!), I guess some will do well. Smallish dogs could turn out to be pretty effective predators, maybe competing with cats for some prey. Genetics will be very interesting, afaik dogs are basically one species but not all breeds can interbreed because of size - so you have a ring species (look it up) without a nice, ring shaped spatial distribution. Also note that smallish mammals tend to make good survivors of mas extinctions and dogs are not too big and eat smallish mammals.


    With most domesticated animals and plants, things get weird. Some (like maize) won't survive the extinction of humanity. For the rest, things get a bit weirder. They're often actually members of species that have both wild and domestic forms. Yes, the domestic forms often have different Linnaean names, but that's a formality. If they're 100% interfertile with wild forms, they're more or less the same species (but see below).

    To put it simply, breeds are highly inbred, genetically uniform populations within a much broader species. They're not yet separate species, and they are kept uniform by harsh human control of their breeding (think mutts).

    When humans go away, the breeding barriers largely break down. While a great dane won't have sex with a chihuahua, there are plenty of intermediates. As a result, what will likely happen is that there will be this great mongrelization of most of our domestic species. Some speciation will eventually occur, but that will happen in isolated places. Many islands will eventually evolve their own dog, cat, and hemp species, for example.

    Dogs are weird because the canids tend to interbreed anyway. Wolves, coyotes, dogs, all have interbred in the past, so while there are species barriers, they're pretty porous. On the continents, I expect the stew to keep mixing. The same is true for some other weirdos, notably members of the wheat tribe (wheat, spelt, rye, etc.).

    Note that mongrelization doesn't just depend on humans going extinct. Civilization crashing will do it just as well. If you want an example, note how many of the Roman breeds of dogs, horses, or plants we still have on hand. To my knowledge, mastiffs might be the only ones. Many of the others are more modern recreations.


    Dogs are weird because the canids tend to interbreed anyway.

    I'd expect any post-human Earth to have dogs all over the place. Uncontrolled breeding seems to converge toward medium sized, brown, nondescript mutts; as you write, we can expect many local variations. Locally varied conditions and founder effects would both be at work.

    It occurs to me that house cats are smaller than most of their wild cousins, some of which are very large carnivores indeed. One lingering effect might be to have introduced the felids to smaller more abundant prey. How stable a role they could carve out over megayears is open to question but it's already obvious that it's much harder to wipe out colonies of feral cats than an equal mass of leopards or tigers.


    I have been lucky enough to see ravens on an almost daily basis. They have an immense range of vocalisations and very complex social interactions, as well as very adaptable feeding strategies.

    Who knows, maybe a descendant of corvids will be the next technological species?


    IIRC correctly, in the Red Sorhum novel, after fending off Japanese invaders and one or the fraction of the chinese civil war, the remaining defenders of the village fight of a large horde of huge dogs, that grew fat during the war and civil war.

    Anyways, a few stupid ideas for futuer evolutions: Crocodiles -> Aqua pigs: Crocodiles eat fruit on occasion already, some develop a habit and dig up submerged roots of of reeds and the like (IIRC, cattails have roots comparable to potatoes in nuttrition value). The teth become more boar like to enable digging. Instead of carrying a large gut around, they simply take their time with digestion, crocodiles don't eat that often anyway. I'm thinking more omnivore than strict herbivore.

    Large birds -> Bipedal wolves: Some species of flightless largish birds starts to hunt as packs, essentially behaving like wolves or similar. How would a bunch of 50-60 kg mini-ostriches take down a deer? Not sure but might be doable.

    Horse -> Wooly mammoth 2.0: In the coming steppes of warmed up siberia, feral horses grow (cold climate favors large size) and adapt: hooves become multitols for fendig of predators, digging in snow, scraping of tree bark (in a pinch) and running over soft ground, longer necks to reach the ground despite the height.

    I read in HED about the theory that termites developed their mound building habit in the dung heaps of large dinosaurs - now if you have large mammals that somehow develop the habit of shitting all in the same plae, maybe some mole rats could build their tunnels there?

    Eusocial beetles: I don't know how or why beetles should develop eusociality, but since large beetles are far larger than large ants individually, it would be cool in a creepy way.

    ? -> Ant mound eater: Forest ants build huge mounds, some animal develops enough resistance (or a clver trick, maybe drowning the mound before eating and eats the mounds wholesale. Grubs and ants and what is edible of the mound material get digested, the rest ends up as shit. Needs to be large animal, unsure of the candidate.

    Hunting hedgehogs: Hedgehogs form bands that together block the exits of rabbits dens etc., by sitting down in the exit and forming the famous ball. When the rabbits are too starve to run away from the hedgehogs, they strike.

    Stunnypus: Pltypie have an electricity sense. What i the developed (via a pathway laid down somwhere on heteromeles blog years ago) a longer beak (better antenna) and then the ability to activly electrocute their targets? Time for bigger prey! I imagine a crocodilian livestyle: lie in wait in the mud, surprise a large stun a large mammal with an electric shock, then drown it and eat it. Imagine a band of larger, long beaked platipy lying down on a deer to drown it.


    Some of these have happened before, oddly enough:

    Back in the Mesozoic, IIRC there were some pig-like aquatic croc relatives. Similarly, the "demon duck of doom" (Bullockornis) was a real bird, and birds aren't all that far from Tyrannosaurs. I would be surprised at all if ducks or chickens didn't cough up another clutch of huge birds.

    Unfortunately, I'm not sure horses can get much bigger than they already are. That continual trickle of thoroughbreds breaking their legs running is the little warning that putting huge amounts of weight on single digits leads to a lot of stress. If you want something elephantine, I'd suggest it would evolve (as did elephants) from a currently small animal. Remember that hyraxes are elephant relatives.

    As for the insects, termites and ants are so good at doing what they're doing that I suspect they'll keep doing it for awhile, and other organisms will keep either eating or parasitizing them. The Cenozoic is the age of eusocial insects as much as it is of mammals. While all sorts of things have become eusocial (there are also eusocial shrimps and cockroaches out there), I'm not sure why beetles would do it. If I was to pick a line of beetles, I'd look at dung beetles, since (unlike most of the others) they already indulge in parental care. Most beetles lay eggs and never do anything else to care for their larvae, and that's a really good way to stop eusociality from evolving.

    As for platypus becoming electrically emitting, I'm not buying it, because there's a lot of additional rejiggering of biological structures that has to happen. Heck, IIRC some dolphins are electro-receptive. The thing is, to generate a decent shock, you've got to devote a good chunk of your muscle to being a battery. That's not very compatible with a platypus body plan. If they were the equivalent of an electric eel, they'd be something like 80% bill and probably starve to death.


    "Large birds -> Bipedal wolves"

    I like this. Phorusrhacids (I want one as a pet) have already been mentioned, along with them dying out when mammals started coming across the Panama isthmus and eating their eggs. But as I understand it, they were largely solitary species, which probably didn't help. Maybe a pack species that assigned some pack members as guards over the communal nesting area would do better.


    I recently ran across a mention of periphyton matting and that got me thinking about the remarkably diverse range of species within periphyton, and in turn about ocean surface microbiomes again. (See my commentary on turtles above at #313.)

    The opportunities for interesting life forms is obvious; most people who live near shorelines have some knowledge of intertidal zone and tidal pool ecologies. But the tricky part is finding a semi-stable substrate: some floating thing that doesn't disintegrate quickly. Most floating solids are biological in origin, and not very long lasting once the creating organism is gone. It's easy enough to imagine some kind of floating bromeliad or rootless seaweed but this is apparently hard to evolve, as Earth has only a few examples.

    It's tempting to imagine a lot of commensual species building a complex ecology in seawater swamps bootstraped from seaweed and analogous plants, but science fiction fans can just go read The Demon Breed, as James Schmitz did it back in 1968 and his floatwood islands are as fully realized as anything we'd put together today..

    PS: I happened to run across some internet people in full furious denial that the Pacific Gyre exists, apparently founded on the idea that since it's not a solid continent of garbage it cannot be real. As a comparison, imagine saying that since asteroid belts aren't flying rubble piles as seen in movies therefore they don't exist.


    Kelp and sargassum rafts are useful bases for floating ecosystems. Prof. Mark McMenamin, one of my favorite lunatics (go read Hypersea), posited in an old Discover magazine, that the future would see floating mangroves, with roots covered by sponges that somehow hosted nitrogen-fixing bacteria, and these floating mangrove clumps would pump so much oxygen into the air that the world would go all Carboniferous on us and the continents would burn

    Yeah. There are a bunch of problems with this, but the general one is that wood is only somewhat floaty, and as the float gets heavier, it rides lower in the water, which may make it harder for the tree to take in oxygen. I'm not sure whether it's possible to get to that form from what currently exists on our planet.

    Still, it's a cool idea. I'm not sure whether I prefer the implementation in The Demon Breed or The Door Into Ocean. They both have their virtues. I keep wanting to swipe this idea for my own stories, but I haven't gotten to it yet.


    Isn't a major difficulty with such things evolving that there are not many suitable sites? As in, places like the Sargasso Sea, where currents and winds are such that a viable population can accumulate in one place without too much loss from bits drifting off to less hospitable regions.

    Lake Titicaca, I think, has floating islands made of matted chunks of reeds (or something similar to reeds) that have broken off from the shore. The larger ones have people living on them, maintaining them, and even growing crops.


    There are floating islands all over the place, from Titicaca to the Amazon, slow moving rivers in Papua New Guinea (grasses) and Africa (Papyrus), and floating bogs in the US and Canada. All of them formed in slow-moving waters.

    As for the oceans, there's a gyre in the center of every major ocean, and they seem to be at least somewhat calm on occasion (cf: doldrums). That's how those garbage patches form. The problem with a floating forest is more geometrical: trees don't normally grow as efficient rafts, and if the floatwood doesn't grow in just the right way, it's going to turn turtle during a storm, and that will be the end of the forest.

    If a tree could solve the problem of floating huge amounts of wood, root itself in periphyton, and not sink, it could float in the center of a gyre almost indefinitely. Birds roosting in its branches would bring in a lot of nutrients, and if it could capture even a few of them, it would do pretty well. Still, that initial, physical problem of turning a tree into a boat is what I think sinks floating forests, at least at first glance.


    If it looks anything like a land tree, it's going to have more difficulty remaining in the gyre than sargassum weed does, because that sticky-up bit with the leaves on has tremendous windage. But you could imagine it developing more in the shape of a low, flat, bush or shrub thing, with small and densely-packed leaves, to reduce the windage; and under the water, very long, dense, deep-dangling roots to act as a sea anchor. That would also lower the C of G and make it much more resistant to capsizing. The roots of adjacent plants would be prone to getting tangled in each other, which would help bind together a raft; all the more so if they tended to cross-link at points of contact. On the carnivory theme, it might also develop to entangle fish in the roots. Going for the really wild ideas, perhaps it could entangle sharks and induce them to try to swim in particular directions by selectively releasing shark-attracting chemicals, in order to harness them as station-keeping thrusters before they got to the stage of being food.


    Shark attraction is not as crazy an idea as you might think. There's plenty of documentation of sharks hanging around life rafts in the open ocean, to the consternation of the occupants. This is because the shaded volume under the raft attracts small creatures, which in turn attracts medium sized fish, which in turn attracts fish eating sharks; very few sharks have much interest in humans but not all humans are confident of that.

    I agree with the impracticality of a big vertical land-style tree in this context; a planar body plan seems much more practical. It's not as if plants have to compete for altitude in the open ocean. Something more like a tangle of shrubbery or a carpet of moss sounds completely plausible.

    The Lake Titicaca islands have the advantage of being actively maintained by their residents. Maybe some social insect could take up that role on the oceans? Then we get into fishing termites and the whole discussion goes weird...


    Maybe some social insect could take up that role on the oceans?

    So now I learn that of course there's a submersible saltwater ant.

    I think our fifty million year speculations are tending much too conservative.


    On the other hand, as noted above, fetch or windage hitting above-water trees provides a heck of a lot more force than harnessed sharks would. Since floating debris naturally gets a cloud of life around it in the deep ocean, there's honestly no reason for a floating forest to expend energy trying to move to get nutrients. Nutrients (in the form of animals) will come to it, if it's sufficiently attractive. Keeping the floating forest from sinking under the weight of all the crap it accumulates might be the harder problem.

    As for the submersible ant, it's not an underwater predator per se. Rather, it somehow seals itself into its nest when said nest gets submerged, and they keep the water out during that time. Otherwise, they're simply living in mangroves.

    While I agree that we're being conservative, there's a difference between wildly inventive and impractical. The saltwater ant is simply one of a couple of ant species that have figured out how to colonize a habitat (mangroves) that no other ant lives in. That kind of thing happens all the time. That's less improbable than a tree figuring out how to live and reproduce while floating on the surface of the ocean. While the ocean surface looks inviting, it's such a hellish nutrient desert that few of anything larger than bacteria normally live there. Even floating large seaweed haven't figured out a way to live on the ocean surface indefinitely. It's not impossible, but getting from here to there is, shall we say, a deeply counterintuitive process.


    How about... some shrub or bush that grows near the borders of bodies of water, estuaries, rias, maybe of the kind where multiple leafy bits arise from a continuous and pervasive network of roots (like brambles). Maybe due to rising sea levels or something the ground becomes more liable to inundation, so the plants develop salt tolerance, and, later, also becomes susceptible to erosion; because of the network of roots, the soil gets washed away but the plants don't, and remain anchored by that part of the root network that is still in solid ground. The overhanging rooty borders that develop are an attractive hiding place for fish, and some kind of vague symbiosis develops whereby the roots grow in a shape more attractive to fish and absorb their shit from the water. Eventually the erosion progresses far enough that chunks of plant do start falling off, but by then they're good enough at encouraging fish to shit in their roots that survival is possible...

    I'm sure it's possible to pick lots of holes in that, but on the other hand given 50 million years there's room for even less likely things to happen :)


    There are easier starting points.

    First off, I'd ignore Azolla, Salvinia, Eichhornia and friends. They're floating plants, but too tiny. Water hyacinth (Eichhornia crassipes) is (AFAIK) the biggest floating plant. Now all of these can smother a lake in a layer of dead plants a meter deep, but they're all freshwater plants. The key, I think, isn't that they're salt intolerant (they are, but salt tolerance happens). Rather, the lakes they prefer have a lot of nutrients in them, so they can get away with not having a highly developed root system. All the bigger aquatic plants are rooted in the ground. This includes all the seasonally aquatic trees that live in the flooded forests of the Amazon, all the mangroves, all the salt marsh and coastal swamp plants, etc.

    What we're trying to do here is to figure out how an marine aquatic tree can wean itself from the Earth. To do this trick, it's got to be very nutrient efficient (there's not many nutrients where it's going), it has to be very lightly built (so it can float), it has to be quite tough (because it's going to get hammered by storms, so it can't be brittle), and it has to be attractive to wildlife. This last is the critical trick. Oceanic islands are nutrient magnets, because birds roost in them. Floating kelp beds and similar debris are fish islands, for whatever reason. A floating tree island can work as a nutrient magnet. It's primary problems are flotation, which means it has to lay down a fair amount of very light wood with a very limited nutrient supply, and nutrient retention, which means that it has to either pull something like the staghorn fern trick, or it has to come up with something like McMenamin's proposed sponge symbiosis, where a sponge (or similar organism) grows on the floatwood's dangling roots and acts to acquire nutrients. The thing here is that dangling roots deep into the water is kind of a waste of time, because there's so little there (other than water) that the plant isn't going to get a lot for growing those structures, but they are going to lose those roots to hungry browsers unless they're covered in crap and/or organisms that are providing nutrients to the tree.

    Again, none of this is theoretically impossible. Staghorn ferns hold onto nutrients, as do bromeliads. Mangroves grow in salt water, as do a large number of the Chenopodiaceae (saltbushes), Nypa palms, eelgrass, and a few others. Balsa trees produce light and strong wood, as do bamboos. The real problem is that there's no one plant family or even plant clade where all these traits are combined. We've got things we need scattered among ferns, several divergent groups of monocots, and several different groups of eudicots. Evolutionarily, it's akin to saying that the ideal oceanic animal combines some traits found in insects, reptiles, an amphibian, a platypus, and a human.

    That's where it gets deeply counterintuitive. For a woody plant to make a jump to the ocean, it needs to start from one of the above groups and evolve all the things it is missing. Furthermore, all the intermediate steps need to be both evolutionarily successful themselves and they need to be intermediate in success between the beginning and ending points. This is a weird phrasing, but we're doing the equivalent of going from an insectivore scurrying through the leaves to a flying bat. A half-flying bat is a useless critter, as is a gliding bat the flaps its unelongated front legs (hard to glide with a fluttering front edge). Our putative floatwood ancestor has to evolve things like a crap retention mechanism that makes perfect sense for its life in a marsh. It has to evolve floating wood, even though that probably makes it more vulnerable in a storm. It has to figure out how to be extremely conservative with nutrients, but if it evolves in a salt marsh, the sludge it's growing in is some of the most nutrient rich soil in the world, so it probably has to start on an atoll beach or some such.

    You get the idea. This is why I said above that it's not impossible, but the path from here to there is deeply counterintuitive.

    Or somebody has to genetically engineer such a plant in the month that Charlie's left us before we go extinct (where's that plague again? We should be seeing it by now, if the scenario is correct...)

    Now, if we're talking about an alien world, all bets are off, which is why floatwood forests and The Door Into Ocean are both so much more appealing.


    ... fetch or windage hitting above-water trees provides a heck of a lot more force than harnessed sharks would. Since floating debris naturally gets a cloud of life around it in the deep ocean, there's honestly no reason for a floating forest to expend energy trying to move to get nutrients.

    Agreed; the plants would have very little reason to want to be anywhere but a relatively peaceful ocean gyre. If we want to see biological sailing, it might be more plausible as another creature imposing this on the floating raft. For example, nesting birds might 'sail' their bushes into clusters with other birds of their species.

    Sea birds would love having semi-solid floating things around, but a plant large enough to keep a gull's nest (one or two kilograms, when occupied) fully out of the water isn't going to be the first floater to evolve.


    Water hyacinth (Eichhornia crassipes) is (AFAIK) the biggest floating plant. Now all of these can smother a lake in a layer of dead plants a meter deep, but they're all freshwater plants. The key, I think, isn't that they're salt intolerant (they are, but salt tolerance happens). Rather, the lakes they prefer have a lot of nutrients in them, so they can get away with not having a highly developed root system.

    Sadly, I think you're right. It's too bad; it would be a lot of fun to see evolved weaver ants setting up homes in saltwater tolerant water hyacinth clusters, then raising sail and heading off toward the far horizon.


    This one's better. This is how it starts.


    I agree bears have many advantages but fear they may have too many; it's hard to see what environmental stresses would get bears evolving into tool users faster than more easily threatened and faster reproducing animals. Raccoons and beavers may be closer to the hypothetical sweet spot than bears. We're lacking a lot of information about this process, not all of which we know we don't know, just because we have only one example tool user to study.



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