newt in the throat

Grasslands suddenly spreading across the Arctic about 10,000 years ago helped killed off the woolly mammoth and other prehistoric mammals, suggests a study of ancient Arctic vegetation.

Climate warming after the Ice Age, prehistoric hunters, and even a comet impact have been proposed as reasons for the extinction of the mammoth, woolly rhinoceros, and other oversized “megafauna” that once inhabited Siberia and North America’s far northern plains. 

The new DNA analysis of Arctic vegetation over the past 50,000 years, published in Nature by a team led by Eske Willerslev of the University of Copenhagen, offers a new wrinkle on the climate-warming theory: The great beasts vanished because they weren’t getting enough of the right food.

Some 10,000 years ago, the researchers found, the flowering, woody plants known as forbs—including sagebrush, yarrow, mums, and tansies—disappeared from Arctic steppes, which became more dominated by grasses. That vegetation change was “a likely key reason for the decline and extinction of many megafuana species,” Willerslev says, by email.

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