How did the woolly mammoth stay warm?
To keep warm, the woolly mammoth did more than just be woolly, new research has found.
The lumbering, shaggy-haired woolly mammoth once thrived in the frigid Arctic plains despite having originally migrated from a more tropical climate. A new study has found tiny genetic mutations that changed the way oxygen was delivered by its blood could be responsible for its tolerance to the cold climate.Skip to next paragraph
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The woolly mammoth was an elephantid species and most closely related to today's Asian elephants. It went extinct around 13,000 years ago. But because the mammoth lived in the Arctic, many remains of the species have been found preserved in the permafrost.
Ancestors of both the mammoth and Asian elephant originated in Africa around 6.7 million to 7 million years ago and stayed for about 4 million years before moving up into Southern Europe and then farther up into what is now Siberia and the northern plains of Canada around a million years later.
At around the same time "a cataclysmic event occurred on Earth — the Ice Ages," said Kevin Campbell of the University of Manitoba in Winnipeg, Canada, who led the study into the ancient animal's blood, which is detailed in the May 2 online issue of the journal Nature Genetics.
Mammoths, like their elephant cousins of today, would have been adapted to the warm climate they evolved in. In these climates, an elephant's biggest problem is getting rid of heat -- they do this with their big ears, through which many heat-porting blood vessels circulate. They wave their ears around in the breeze to dissipate that heat.
That perennial elephant problem was reversed for the mammoths once the Ice Ages settled in and "a whole new environment was made" in the Arctic, which had also been warm up until that point in Earth’s history, Campbell said. Now mammoths had to hold in all the heat they could.
"We know that conserving heat became their number-one concern," Campbell told LiveScience.
Mammoths adapted to their new, colder home partly by evolving a "thick, huge pelt," and down-sizing their ears compared with their warmer-dwelling relatives. "Their ears were tiny, like dinner plates," Campbell said, referring to the cold-adapted mammoths.
How other Arctic animals adapted
But Campbell suspected that the mammoths also could have had blood that was better adapted to work in the cold, like many Arctic mammals alive today do.