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Comment by myshpa | Hacker News Reader

https://upload.wikimedia.org/wikipedia/commons/a/ad/Extincti...

Humans were the reason, on all continents.

https://ourworldindata.org/wild-mammal-decline

"By around 10,000 years ago we see a huge decline of wild mammals. It’s hard to give a precise estimate of the size of these losses millennia ago, but they were large: likely in the range of 25% to 50%."

"It wasn’t just that we lost a lot of mammals. It was almost exclusively the world’s largest mammals that vanished. This big decline of mammals is referred to as the Quaternary Megafauna Extinction (QME). The QME led to the extinction of more than 178 of the world’s large mammals (‘megafauna’)."

We lost the biggest animals because those were the ones we hunted. If the reason were to be the fire (which sounds ridiculous), it would have caused the extinction of mammals of all sizes, not just the largest ones.

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> Humans were the reason, on all continents.

The article doesn't disagree, saying both "increased fire activity spurred by people" and "Dr. Dunn emphasized that this pattern could not account for the notable disappearance of large mammals elsewhere in the world at the end of the last ice age".

> If the reason were to be the fire (which sounds ridiculous), it would have caused the extinction of mammals of all sizes, not just the largest ones.

No, not necessarily. A small animal can retreat into a burrow an elephant-sized one cannot. They also breed faster afterwards, allowing their populations to recover more readily.

The mass extinction of large megafauna, all around the world, at roughly the same time, isn't explained by humans (see woolly mammoths). There's far more evidence that it was driven by climate change as the world quickly exited the last glacial maximum.

https://edition.cnn.com/2019/10/08/us/woolly-mammoths-death-...

Last mammoths died 4000 years ago, and they might have even lived longer, if short-term events hadn’t tainted their water and drained their food supply.

It wasn't climate change that killed off the mammoths; it was humans.

https://www.google.com/search?q=mammoth+house&tbm=isch

We ate them all. It was only when there were no big animals left to hunt that we invented agriculture.

And yet, for some reason, ancient humans decided not to eat all the elephants.

No, it was climate change.

The last, small population of mammoths that survived until 4000 years ago on Wrangel Island never came in contact with humans. They died because they were ill suited for the climate they lived in.

Humans got rid of plenty of elephants. "Both" is likely the answer in all of these extinction events.

https://www.nbcnews.com/id/wbna7548514

> One million years ago, elephants and their cousins roamed the five major continents of the earth. Then humans came along. Today elephants can be found only in portions of sub-Saharan Africa and South Asia.

> The two most argued hypotheses for their decline are climatic changes and over-hunting by humans. A recent archaeological expedition dug up information that may support the latter.

> Exploring 41 sites ranging from 1.8 million to 10,000 years old, Todd Surovell of the University of Wyoming found that interactions between humans and elephants matched up with successive waves of human population expansion. As the human populations in those sites continued to grow, the number of elephants shrank and, in some sites, disappeared.

> ancient humans decided not to eat all the elephants

Who knows why? Larger size, slower reproductive rates, and adaptations to colder climates? Maybe elephants were more socially organized and were harder to hunt? Maybe their habitats were not so densely populated by humans? We can only speculate.

> No, it was climate change.

While climate change certainly played a role, it's undeniable that the QME would not have been as extensive if it weren't for human involvement.

> never came in contact with humans

That's not clear, iirc.

Elephants and humans must have evolved together, that could have helped the elephants.

You do realize that the majority of elephant species are extinct and the ones left have less than a fraction of their historic range?

This is a bit of a tangent, but I think the phrase "you do realize" rarely, if ever, seems to add anything to the debate. It sounds patronising at best, and makes people defensive even if it's a useful point.

Climate change potentially caused by catastrophic comet impacts.

It’s both.

Human populations were growing rapidly and simultaneously the period from 50000-10000 was the end of the last ice age

So the going theory is that the original areas of climate for which mega fauna were most populous, was effectively reduced increasingly over time as a result of warming, which humans were able to capitalize on to the point where we kind of “finished the job.”

This is effectively, how we see extinction patterns around the globe. Whereas humans aren’t necessarily the primary or only cause, but they do make a big enough exogenous impact to cause a collapse.

How big of a population are we talking here

https://ourworldindata.org/wild-mammal-decline

"What’s most shocking is how few humans were responsible for this large-scale destruction of wildlife. There were likely fewer than 5 million people in the world. Around half the population of London today."

Well the estimates are kind of all over the place but basically growing from ~1M - 15M over the course of 40000 years, before the Neolithic explosion

It seems somewhat incredible that mega fauna survived the previous two dozen or so ice ages just fine then went extinct as soon as humans figured out how to live in huts.

Something so innocuous turning catastrophic... But don't worry guys AI will totally 100% be aligned with not fucking humanity over.

Given historical and prehistorical evidence, I think it fair to say that even in the cases where humans were not responsible, it was not through lack of trying. Human societies gorged themselves until they had to adapt to scarcity, at which point I think we started developing concepts like living in harmony with nature, agriculture and land management.

> "Humans were the reason, on all continents."

Except the numbers don't really stack up. 10-15k years ago the entire global population of humans was, at best, a few million. And a single megafauna kill would produce enough meat to feed an entire community for weeks. Humans would have had to have been extremely bloodthirsty and systematic in their slaughter, and must have been wasting enormous quantities of meat.

Also, the regions where some megafauna species survive into modern times (ie: Africa and South Asia) were where most of the humans lived. Wouldn't we expect those species to have gone extinct too?

It's certainly possible that humans helped finish off megafauna populations that were already scattered, distressed, and in decline. But it's unlikely that we were the primary or only cause.

> "We lost the biggest animals because those were the ones we hunted."

There's plenty of evidence that ancient humans hunted animals of all sizes. Why would we only go after megafauna as they became rarer and rarer? Instead of smaller species that were far more numerous and accessible?

> And a single megafauna kill would produce enough meat to feed an entire community for weeks.

Meat spoils in warm weather within days. Weeks would be assuming they had refrigeration. We're not sure when the practice of curing and drying meat started, and if they had not been practicing that... then it would be a megafauna every few days.

> https://upload.wikimedia.org/wikipedia/commons/a/ad/Extincti...

There are several findings of humans being present in North America much earlier than 13 000 years ego. One recent paper in Science: https://www.science.org/doi/10.1126/science.abg7586

A longer list in a thread 6 months ago: https://news.ycombinator.com/item?id=34525911

Would be interesting if the myth of Dragons breathing fire was because we used fire to kill the largest/scariest megafauna.

We probably used fire to cook them with, and probably cause a lot of accidental fires in the process ;) Also bare in mind that except for africa those megafauna would have been relatively tame and way too unsuspecting of meat eating humans.

There's a lot of theorizing that early sapiens intentionally set fires to clear thick, impassable forests and kill game in the process. The cleared areas would make post-fire hunting easier as well.

This is still practiced to an extent by the Aboriginal Australians.

https://en.wikipedia.org/wiki/Fire-stick_farming

https://en.wikipedia.org/wiki/Cold_fire_(Noongar_fire_type)

> thick impassable forests

Trad burning in Australia has largely been to cool burn undergrowth in the forest areas (relatively small land area) and to patch burn open grass lands (majority of area)

eg: https://youtu.be/wZL5rITqpwU?t=208

I note that the megafauna extinction was done by people of all races and creeds, long before capitalism existed.

This, I think, is part of the controversy.

In Australia there's this "noble savage in tune with their environment" thing about the Indigenous people; that they are custodians of the land and live in harmony with nature. The idea that they are also responsible for the mass extinction of the megafauna is incompatible with this idea, and therefore unacceptable.

I've been in Australia 60 odd years, frequently in contact with anthropologists in the Kimberley and PNG.

The noble savage trope died out years ago - haven't seen much of that in any serious circles since the back to nature french quasi-anthro types were grooving to La Vallée by Barbet Schroeder (with the Pink Floyd soundtrack).

> The idea that they are also responsible for the mass extinction of the megafauna is

.. pretty hard to land, save for the possibility of a small number.

https://en.wikipedia.org/wiki/Australian_megafauna

Head on down to "Causes of extinction" and read carefully, there are a lot of some's.

    New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction for some of the megafauna in Australia.

The evidence we have (sure, there may be unknowns) is that the bulk of the megafauna were dwindling as a result of the environmental changes following the end of glaciation.

Humans in Australia appear to be responsible for, at most, the final death blow to a few of the species that were on their way out already.

If you have evidence to the contrary I'd gladly accept it.

No evidence, but anecdata. Glad to hear it isn't taken seriously by actual anthropologists. Thanks for the info :)

Doesn't explain the ones frozen in place still in the process of chewing grass.

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