The extinction of woolly mammoths blamed on climate change, not human hunting

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A trio of woolly mammoths trudge across snowy terrain. Behind them, snow-capped peaks rise above dark green fir forests.

Daniel Eskridge

About 4000 years ago, the last majestic the woolly mammoth wandering the Earth has disappeared, and for decades scientists believed these colossal elephant ancestors were extinct because they were relentlessly hunted by humans. DNA analysis of ancient animal trampling grounds, however, reveals a different story.

The most likely culprit, the researchers said, was rapid climate change that ultimately wiped out the creatures’ food supply. But in addition to solving the mystery of the endangered mammoths, these findings may offer insight into the fates of other species if our present the climate crisis is not under control.

“We have shown that climate change, especially precipitation, directly drives vegetation change – humans have had no impact on [the mammoths] at all based on our models “, Yucheng Wang, zoologist at the University of Cambridge and first author of the article published Wednesday in the journal Nature, noted in a report.

Co-author Eske Willerslev, a researcher at the University of Cambridge and director of the Lundbeck Foundation GeoGenetics Center at the University of Copenhagen, added: “This is a brutal lesson in history and shows just how much climate change is unpredictable – once something is lost, there is no turning back. ”

These gentle beings who dined on the grass and the flowers lived alongside the Neanderthals. Although many encounters may have been peaceful, animals were a popular commodity when it came to making fur coats, musical and art instruments, and hearty meals. This is because of their thick chocolate colored fur, huge and sturdy tusks, and huge size.

mammoth-tusk-on-the-logata-river-bank

A mammoth tusk on a bank of the Logata River in Russia.

Johanna anjar

They weighed around 6 tons and were around 13 feet (4 meters) tall – as Wang puts it, woolly mammoths could “reach the height of a double-decker bus”.

“Scientists have been arguing for 100 years as to why the mammoths are extinct,” Willerslev said. “Humans were blamed because animals had survived millions of years without climate change killing them before, but when they lived alongside humans they didn’t last long and we were blamed. for having driven them to death. “

It makes sense that prehistoric humans are believed to be behind the eventual disappearance of woolly mammoths instead of climate change. These animals somehow withstood the Ice Age around 12,000 years ago – Disney’s whimsical Ice Age movie has some thoughts on this – but the researchers of the new study decided to dig a little deeper. more deeply.

Over a period of 10 years, Willerslev led a team to dissect DNA fragments collected from the arctic soil where mammoths grazed. The samples were collected over 20 years and analyzed using a method called DNA sequencing.

Shotgun DNA sequencing is an indirect way to create genetic profiles without requiring the physical presence of a person or animal. Instead of collecting genetic information from bones or teeth, the method sequences DNA from traces of urine or rejected cells. Scientists have also used this tool to follow the movement of COVID-19 by creating DNA profiles from wastewater scraps.

Researchers who looked at ancient mammoths found that populations of huge animals – discovered using the sequencing method – were being depleted at a rate consistent with the rapid rate of climate change at the time. Willerslev says this is because “as the climate warmed, trees and plants in wetlands took over and replaced mammoth grassland habitats.”

modern-arctic-landscape-1

The modern arctic landscape.

Inger Greve Alsos

“When the climate got wetter and the ice started to melt, it resulted in the formation of lakes, rivers and marshes,” he said. “The ecosystem has changed and the biomass of the vegetation has declined and would not have been able to support the mammoth herds.”

Wang also notes that prehistoric humans would likely have spent most of their time hunting animals much smaller and easier to capture than huge woolly mammoths, suggesting that their impact on animal extinction was arguably smaller than that. ‘we didn’t think so intuitively.

Another important aspect of the results, said Wang, is that “we were finally able to prove that it was not just climate change that was the problem, but the speed of it that was the last nail in the coffin – they weren’t able to adapt quickly enough when the landscape changed dramatically and their food became scarce. “

Such speed is why researchers have naturally drawn parallels between what happened then and what seems to be in store for us now. For example, our global temperature is rising so rapidly that the old target of many countries limit the increase to 1.5 degrees Celsius (2.7 degrees Fahrenheit) is now considered nearly impossible by the UN Intergovernmental Panel on Climate Change. That is unless immediate and drastic action is taken, they say.

“This shows that nothing is guaranteed regarding the impact of dramatic climate change,” said Willerslav. “The first humans would have seen the world change beyond recognition. It could easily happen again, and we cannot take it for granted that we will even be there to witness it.”

“The only thing we can predict for sure is that the change will be massive.”


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