Like in a TV crime drama, DNA evidence proved crucial to solving the mystery of an ancient cold case from a very cold time. A recent genetic analysis provided evidence that seems to acquit humans of causing the woolly mammoth's extinction. Instead, it seems the climate may have committed mammoth murder.
The DNA analysis suggested that mammoths nearly died out 120,000 years ago during a warm period, long before human hunters would have been a serious threat. The prehistoric pachyderms bounced back, only to decline again approximately 20,000 years ago.
Oddly, 20,000 years ago was actually the height of the last ice age. The authors of the study, published in the Proceedings of the Royal Society B, suggested that the environment may have become too cold and disrupted the grassland habitat the mammoths depended upon. Then, when the climate warmed again, the animals' preferred ecosystem was taken over by tundra and forest.
The one-two climatic punch may have been the ultimate reason for the furry elephant's demise, but humans may have helped them along. Archeological evidence, such as cave paintings and ivory carvings, suggest that humans hunted ice age elephants and used them as a source of raw materials.
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However, a single mammoth would have provided tons of meat, enough to feed hundreds of humans for weeks, according to the Pennsylvania State University's Mammoth Genome Project. Since human populations were so low at the time, it seems unlikely that scattered bands of hunters would have been enough to extinguish the ice age elephants in Europe and Asia without help from a changing climate.
In the Western Hemisphere, humans were munching on mastodons, a relative of the woolly mammoth. At the Manis mastodon site in Washington state, a butchered mastodon was found with the tip of a spear embedded in its rib. The point, made from another mastodon's bone, would have needed to be at least 27-32 cm (10.6-12.6 in.) long to penetrate the skin and flesh of the ancient beast, according to a study in Science. The site dated to 13,800 years ago.
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The last population of woolly mammoths died out nearly 4,000 years ago on isolated Wrangel Island in the Arctic, although they had disappeared from the mainland long before. Considering the importance of the ancient, hairy elephants to humans as artistic inspiration and food, the extinction of the mammoth and mastodon may have seriously disturbed our ancestors' societies and lifestyles.
IMAGE: A 39,000-year-old female Woolly mammoth, which was found frozen in Siberia, Russia is pictured upon its arrival at an exhibition hall in Yokohama, south of Tokyo, July 9, 2013. The mammoth will be on display until Sept. 16, 2013. (Toru Hanai/Reuters/Corbis)