Scientists behind a new genomic study now claim that Earth’s last woolly mammoths were wiped out in an extreme storm or plague, meaning that had an extinction event not occurred, they could still be alive to this day.
These giant Ice Age beasts roamed the tundras of North America, Europe and Asia 300,000 years ago. They subsequently became extinct about 4,000 years ago on an isolated island off the coast of Siberia in the Arctic Ocean.
The latest analysis shows that a few hundred woolly mammoths were holed up on the tiny Wrangel Island for about 6,000 years, but scientists say they did not die out due to inbreeding. The Guardian reported.
The long-held theory was that woolly mammoths eventually accumulated enough damaging genetic mutations to cause a ‘genomic fusion.’
“We can now confidently reject the idea that the population was simply too small and that they were doomed to extinction for genetic reasons,” said evolutionary geneticist Love Dalén of the Center for Paleogenetics, a collaboration between Stockholm University and the Swedish Museum of Natural History.
Woolly mammoths traversed the Ice Age tundras of North America, Europe and Asia as long as 300,000 years ago. They later became extinct approximately 4,000 years ago on an isolated island off the coast of Siberia in the Arctic Ocean.
Scientists now believe that the mammoths died from a random event, such as a bird flu or a storm, and not from inbreeding as previously thought.
“This means that it was probably just a random event that killed them, 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, which date back 50,000 years.
In the photo: Professor Love Dalén
They found that the prehistoric creatures hit a “severe bottleneck” once they became trapped on Wrangel Island due to rising sea levels as the Earth warmed.
At one point during the Holocene period (11,500 years ago to present), the total population was eight people or less.
“These findings suggest that Wrangel Island may have been founded by a single herd of woolly mammoths,” the study said.
The study’s authors said one would normally expect a species to undergo “accelerated genomic decline,” but that was not what happened.
“The population recovered quickly after the bottleneck and subsequently remained stable. More precisely, we even found evidence that the recovered population was large enough, or possibly changed its behavior, to avoid inbreeding with close relatives… throughout 6,000 years of isolation on the island,” the study reads.
So if they finally managed to avoid inbreeding, what killed them all?
Wrangel Island, where woolly mammoths made their last stand as a species, is seen just above the northeastern tip of Russia.
Extinct woolly mammoth tusk. It is about 4,000 years old and was found on Wrangel Island.
It’s unclear, and will probably never be known for sure, but Dalén believes something like bird flu could have doomed the species.
“Perhaps mammoths would have been vulnerable to that given the reduced diversity we identified in immune system genes. Alternatively, something like a tundra fire, a layer of volcanic ash, or a really bad weather season could have caused a year of really bad growth for plants in Wrangel.
“Considering how small the population was, it would have been vulnerable to these kinds of random events,” Dalén said, adding: “It seems to me that maybe the mammoths were just unlucky.”
The paper’s lead author, Marianne Dehasque from Uppsala University, told the Guardian that this new story of how mammoths died contains a lesson for the world today, as biodiversity declines every year.
The World Wildlife Fund’s 2022 Living Planet Report found that wildlife populations have declined by an average of 69 percent over the past 50 years.
“Mammoths are an excellent system for understanding the current biodiversity crisis and what happens genetically when a species hits a population bottleneck because they reflect the fate of many current populations,” Dehasque said.
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