> 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.".
10,000 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.
If 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.
> Sloths weren't always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge—up to 4 tons
No, modern sloths are not descended from giant ground sloths. The rest of the article might be okay, but it's hard to trust it after a mistake like that.
> But some archaeologists say it's hard to imagine that humans would repeatedly traverse a site and leave no stone tools.
Those tools were really valuable. They busted their butts, making them, and wouldn't want to toss them aside, just because they got chipped or cracked. They are much more likely to throw them into a "spare parts bag," and keep them around.
Today's throwaway culture is actually pretty new, in human history. Just hang around some poor folks, to see radical conservation, in action.
If you walk the mountains of Nevada along the fossil shoreline where the Lahontan[0] civilization thrived, you will regularly find large quantities of neolithic trash strewn about. Broken, half-finished, or abandoned stone tools are ubiquitous. It takes little effort to find obsidian arrowheads, some in perfect condition.
The preponderance of the evidence is that these were viewed as disposable artifacts, use once and throw away. If they were actually valuable, they could have picked these up in the same way we pick them up today. It would have essentially been "free money" lying on the ground. Yet for some reason, in all the intervening millennia, so few people did that modern humans can find them everywhere.
Lithics were, broadly speaking, more akin to how we treat plastics than metal tools. Lithic production results in enough waste that archaeologists give the waste a special name ("debitage") and even use it for destructive testing that would be unthinkable for more significant / less voluminous artifacts.
That leaves other evidence that's been looked for. Additionally, the Eurasian cultures that peopled the Americas are all known to have been heavy lithic users.
Somewhere, I have an old stone hand axe. It's really well-made. Not sure where it's from, but I believe it came from a European Stone Age dig, about fifty years ago (probably stolen. People weren't so circumspect, in those days).
Eels and tuna lived for millennia also, and will be extinct in a couple of human generations. When ecosystems collapse, they do it really fast, even after years of abuse.
I wonder how long it will be before other theories of Graham Hancock are found to be plausible or true instead of him being dismissed as a crackpot fringe conspiracy person?
Which of Graham Hancock's claims do you think this supports? It certainly isn't the one about a global seafaring proto-British empire from the last ice age, considering how far inland it is, the technology is off, and it vastly predates his hypothesis for the global apocalypse.
The Santa Elena Rock shelter people have been making this argument for years now. Between the questionable lithics, dating, and excavation methodologies they don't have sufficient evidence to support the claims they're making and they've offered no convincing explanations for why the standard of evidence should be lowered given the massive chronological issues their dates would suggest (<5000 years after Yana 10k miles away!).
I wonder how long it will be before theories, beliefs, superstitions, hunches, are no longer combined with grievance and pride and packaged up as somehow empirically relevant.
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.".
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