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> There was this idea that humans arrived and killed everything off very quickly—what's called 'Pleistocene overkill,'" said Daniel Odess, an archaeologist at W
by Qem 2y ago
> There was this idea that humans arrived and killed everything off very quickly—what's called 'Pleistocene overkill,'" said Daniel Odess, an archaeologist at White Sands National Park in New Mexico. But new discoveries suggest that "humans were existing alongside these animals for at least 10,000 years, without making them go extinct.
I don't think there is a contradiction here. Indeed we could have them get extinct, it just took a long time by human standards, ~10 millennia. I don't know how many mastodons or giant sloths/armadillos there was in Americas before humans made landfall here. But I'd guess about 10 million of each. If they took about ten years to reach sexual maturity, that gives us about 1000 generations of megafauna in this time window. To get their population down from 10 million to just one in this time, each generation had to be smaller than the predecessor, but on average could still retain log(10^-7)^-1000 ~= 98.4% of its size. Even if stone age tech enabled humans to overhunt them consistently only by a slight amount, ~1.6% each generation, they still would end extinct in 10,000 years. So it was not "without making them go extinct". It was "while making them go extinct.".
- Swizec 2y ago10,000 years is quite a lot in human time. The pyramids were about 5,000 years ago and look how much has happened since. By comparison, we killed off the Dodo in, what, less than 10 years? I think it’s fair to talk about 10,000 years as a long time. Sure it’s barely a blink in geologic time, but we’re talking about the human perspective here.
- Aloisius 2y agoThe Dodo lived on a tiny island and it was driven extinct largely by invasive species brought by humans. It took humans quite a bit longer to drive say, the tarpan, to extinction.
- HeatrayEnjoyer 2y agoAnatomically modern humans first descended around 200k ago. 10k is short.
- potato3732842 2y agoIf megafauna population is constrained by food availably then slight (a couple percent annual mortality) hunting pressure will not do all that much to reduce overall population. You can look at modern game animal populations to see how the feedback loops work.
- asdff 2y agoHumans probably didn’t exert hunting pressure alone. They might have exerted spacial pressure securing their camps. They might have exerted pressure competing for the same resources (food or small game) as the megafauna.