Scientists say freak event killed woolly mammoths

Scientists behind a new genomic study now say that Earth’s last woolly mammoths were wiped out by an extreme storm or disease outbreak – meaning that if an extinction event had not occurred, they could still be around today.

These giant Ice Age beasts roamed the tundras of North America, Europe and Asia 300,000 years ago. They then disappeared about 4,000 years ago on a remote island off the coast of Siberia in the Arctic Ocean.

The latest analysis shows that a few hundred woolly mammoths were confined to the small Wrangel Island for about 6,000 years, but scientists say they did not die because of inbreeding, The Guardian reported.

The long-held theory was that woolly mammoths eventually accumulated enough harmful genetic mutations to cause a “genomic fusion.”

“We can now confidently reject the idea that the population was simply too small and was doomed to extinction for genetic reasons,” said evolutionary geneticist Love Dalén of the Center for Palaeogenetics, a collaboration between Stockholm University and the Swedish Museum of Natural History.

“That means it was probably a random event that killed them off, and if that random event hadn’t happened, we would still have mammoths today,” he continued.

Dalén and his colleagues analyzed the genomes of 21 mammoth specimens found on Wrangel Island and the Siberian mainland, representing 50,000 years of existence.

They found that the prehistoric creatures hit a “severe bottleneck” once trapped on Wrangel Island due to rising sea levels linked to global warming.

At one point in the Holocene (11,500 years ago to the present), the total population was eight or fewer.

“These findings suggest that Wrangel Island may have been founded by a single herd of woolly mammoths,” according to the study.

The study authors said one would normally expect a species to experience “accelerated genomic decline,” but that is not what happened.

“The population recovered quickly after the bottleneck and remained stable thereafter. Specifically, we even found evidence that the recovered population was large enough, or perhaps changed its behavior, to avoid inbreeding with close relatives… throughout 6,000 years of island isolation,” can we read in the study.

So if they eventually managed to avoid inbreeding, what killed them all?

Click here to resize this module

It’s not clear, and it will probably never really be known with precision, but Dalén thinks something like avian flu could have doomed the species.

Other theories put forward by researchers include a severe weather event or a sudden accumulation of volcanic ash, which would cause a food shortage on the island.

“Perhaps mammoths would have been vulnerable to this given the reduced diversity we identified in immune system genes,” Dalén said.

“Alternatively, something like a tundra fire, a volcanic ash layer or a very bad weather season could have caused a very bad growing year for the Wrangel plants.”

“Given the small size of the population, it would have been vulnerable to such random events.”

“It seems to me that the mammoths may have just been unlucky.”

And while it may seem like a grim story of sudden extinction, lead author Marianne Dehasque of Uppsala University says she prefers to see it as a positive.

She told MailOnline: In a way it’s a message of hope because it shows that small populations are not necessarily doomed to extinction.

This could be good news for existing species such as Siberian tigers or snow leopards, whose populations have been reduced to extremely small sizes.

This new story about the disappearance of mammoths also has lessons for today’s world, as biodiversity declines more and more every year.

The World Wildlife Fund’s Living Planet 2022 report reveals that wildlife populations have declined by an average of 69% over the past 50 years.

“Mammoths are an excellent system to understand the current biodiversity crisis and what happens genetically when a species hits a population bottleneck, because they mirror the fate of many current populations,” Dehasque said.