What killed the Woolly Mammoth?

Long long ago in a [not so] faraway land, lived a giant beast. It weighed 8 tons, and it stood 12 feet tall with tusks almost as long. Its other teeth were the size of shoe boxes. It was the woolly mammoth--a close relative to today's elephant.

Woolly mammoths first appeared on earth 2 million years ago, and they once inhabited most of the world--including North America. We know so much about mammoths because many well-preserved carcasses have been found. Most recently, in 1997, a 9-year-old boy in Siberia discovered a fully intact woolly mammoth carcass. Also, many ancient cave drawings have depicted mammoths and their interactions with humans.

Over the years, there have been spirited debates among paleontologists and anthropologists about why woolly mammoths went extinct. Some say it was due solely to climate change, while others claim that hunting by humans did them in. Another theory yet suggests that woolly mammoths should still be roaming the earth, but that a virulent disease led to their demise.

Last week, the results of a recent study by Spanish researchers appeared in the journal PLoS Biology (Public Library of Science). Their research, which was based on climate models and fossil remains, concluded that climate change drove mammoths to the edge of extiction, and then human hunting pushed them over that edge. The warmer climate led to catastrophic loss of habitat, and they became relegated to 10% of their once-available habitat. With more hospitable conditions for humans, they were able to move into once-unihabitable areas to hunt mammoths. However, by that time (only about 6,000 years ago) humans would only have had to kill one mammonth each every 3 years to push the species to extinction.

Climate change remains a hot issue (pun intended) for our planet today. But as history has evidenced, our climate has always been changing--and it always will be.