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Ancient fires drove large mammals extinct, study suggests

nytimes.com

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Re: Ancient fires drove large mammals extinct, study suggests

#71

Post by AbrahamParangi »

codexb wrote: post #9

I'd be highly skeptical of this claim. Large megafauna around the entire world began dying off both before and after the last glacial maximum, even in areas where there wasn't a significant human presence. The fact that they died off in North America around that time, too, isn't that surprising. It's also worth noting that at that time, a large part of North America was covered in savanna, which is among the most hig…

Hold on though, because the correlation between “human arrival” and “megafauna extinction” is extremely high. The timeline of megafaunal extinctions goes: Africa, then Eurasia, then Australia, then North America, and finally South America. No points for guessing the order that humans colonized those continents.

In the few historical examples of human introduction to a new ecosystem (New Zealand and Madagascar) within a few hundred years of arrival we’d eaten every animal bigger than a cat.

Re: Ancient fires drove large mammals extinct, study suggests

#72

Post by photochemsyn »

If you read the study itself, it claims that it's still hard to say what the relative roles of ice age climate change cycles vs. human predation were on the extinction of large Paleocene mammals in North & South America (and Australia):

> "Despite decades of research on extinction causality, the relative importance of late-Quaternary climate changes and spreading human impacts have been difficult to disentangle because poor chronological resolution in the fossil record has precluded alignment of these rapidly occurring, tightly linked phenomena."

However, it seems pretty clear that wherever humans showed up into new habitats where humans and large animals didn't have a shared ecological-evolutionary history (i.e. not Africa or Eurasia) extinction rates among the megafauna shot way up:

https://ourworldindata.org/quaternary-megafauna-extinction

> "Africa was the least hard-hit, losing only 21% of its megafauna. Humans evolved in Africa, and hominins had already interacted with mammals for a long time. The same is also likely to be true across Eurasia, where 35% of megafauna were lost. But Australia, North America, and South America were particularly hard-hit; very soon after humans arrived, most large mammals were gone. Australia lost 88%; North America lost 83%; and South America, 72%."

Maybe large animal populations had shrank due to the spread of glaciers during the Last Glacial Maximum era (c. 25 kya) so they were more vulnerable, but the new factor (relative to the past 2.5 million years of ice age cycles) was the human predation.

Re: Ancient fires drove large mammals extinct, study suggests

#74

Post by FrustratedMonky »

The next set of wild fires will eliminate the current dominant mega fauna.

The common HOMO-Extreme-BMIans.

Or in the vernacular, Large Human Corporate Drone.

Typically feeding on vast quantities of cheese-wiz over bacon fries, their combined fat mass contains the combustible energy of the worlds combined nuclear stockpiles.

Re: Ancient fires drove large mammals extinct, study suggests

#75

Post by cyberax »

Blahah wrote: post #4
cyberax wrote: post #3

More likely, early humans simply killed off the large herbivores, and the large predators simply starved. This happened in Australia. All the local megafauna disappeared rapidly once humans settled in.

The fire hypothesis is compatible with what you said. The idea is that humans either directly or indirectly caused frequent and vast wildfires that destroyed ecosystems, and those fires either killed animals directly or destroyed the resources they needed to survive.

Not really? Megafauna disappeared everywhere in Americas, including in the Central and South America, that are not susceptible to massive wildfires.

It's far more likely that people simply poked animals to death with sharp sticks.

Re: Ancient fires drove large mammals extinct, study suggests

#76

Post by [deleted] »

FrustratedMonky wrote: post #74

The next set of wild fires will eliminate the current dominant mega fauna. The common HOMO-Extreme-BMIans. Or in the vernacular, Large Human Corporate Drone. Typically feeding on vast quantities of cheese-wiz over bacon fries, their combined fat mass contains the combustible energy of the worlds combined nuclear stockpiles.

[deleted]

Re: Ancient fires drove large mammals extinct, study suggests

#77

Post by dimmke »

Sometimes I go down these Wikipedia rabbit holes, and one of the most fascinating to me is extinct animals that were not dinosaurs.

Specifically, how a lot of mammal apex predators are similar to extinct versions, just like, half the size. Like the American Lion and Direwolf.

Also how this was relatively recent, as others have pointed out they think that a lot of these species went extinct around 10,000 years ago. That fits even conservative estimates of when humans had migrated to the Americas.

This is an aside, but I found it really fascinating. Alligators and crocodiles are kind of obviously in the same area from an evolutionary standpoint (they're both in the Order Crocodilia), and they're both thought to be incredibly old - 30 million+ years.

But there are only 2 species of Alligator left in the entire world. There's the American alligator which is fairly plentiful all around the Southeast United States and a slightly smaller critically endangered variant in China. There's 18 species of Crocodile, and they're in all the Americas, Australia, New Zealand, all of Asia and a huge portion of Africa. And then I learned about Caimans which I didn't even know existed before. It really goes to show how some branches can be so much more wildly successful than others.

Re: Ancient fires drove large mammals extinct, study suggests

#78

Post by magicalhippo »

ceejayoz wrote: post #70
magicalhippo wrote: post #67

Earlier quoted context omitted.

Not directly related but I recall watching a "documentary" on Discovery where this guy claimed that several monuments across the globe all matched up star patterns and similar astrological events from around 12k years ago IIRC. What I recall best was some pyramids ligning up with how the stars would have been back around that time, but they've since drifted apart. He also talked about Angkor Wat and some in South Ame…

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

Thanks, that must be the guy. His 10500 BC lines up with 12k years ago, but yeah...

Re: Ancient fires drove large mammals extinct, study suggests

#79

Post by dotnet00 »

magicalhippo wrote: post #67
pmayrgundter wrote: post #10

Seems that Younger Dryas Impact Hypothesis might fit these observations too. "We obtained radiocarbon dates on 172 specimens from seven extinct and one extant species... spanning 15.6 to 10.0 thousand calendar years before present (ka)." YDIH event is estimated at 12900 BP and includes vast wildfires in its scenario, including in North America. Contrast that with the idea that humans have been in Sapiens form for 200…

Not directly related but I recall watching a "documentary" on Discovery where this guy claimed that several monuments across the globe all matched up star patterns and similar astrological events from around 12k years ago IIRC. What I recall best was some pyramids ligning up with how the stars would have been back around that time, but they've since drifted apart. He also talked about Angkor Wat and some in South Ame…

Are you maybe thinking of Ancient Aliens?

I remember an episode like that, IIRC it also had some crazier claims like pyramid complexes resembling calculator circuit boards.

Re: Ancient fires drove large mammals extinct, study suggests

#80

Post by marcus_holmes »

BurningFrog wrote: post #31
myshpa wrote: post #8

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 e…

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.

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