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Asia's Tibetan Plateau is the world's highest place. It is four times the size of France, and home to most of the world's tallest mountains. And it may be that its deep chill played a role in the evolution of some of the world's most charismatic animals.
NPR's Christopher Joyce has a story about a woolly rhino found on the roof of the world.
CHRISTOPHER JOYCE: The woolly rhino - two tons, two tusks, lots of hair and lots of attitude - was an Ice Age giant. It hung with woolly mammoths and giant sloths and other Ice Age behemoths in Europe and Asia, starting about two-and-a-half million years ago. But Xiaoming Wang was shocked when he found a three-and-a-half-million-year-old rhino skull on the Tibetan Plateau.
Mr. XIAOMING WANG (Natural History Museum, Los Angeles County): It caught us by complete surprise that they are actually up in the high plateau well before the Ice Age has started.
JOYCE: About a million years before the Ice Age started, in fact. Wang, with the Natural History Museum of Los Angeles County, thinks his discovery shows that at least some animals were prepared for the Ice Age.
Mr. WANG: At least in the case of woolly rhino, it actually adapted itself in the cold environment in the Tibetan Plateau before the Ice Age has even started.
JOYCE: Those adaptations included hairiness, of course, and a big body, which actually does well in cold weather. As you increase the volume of a body, say, what's inside the skin, the body's surface area doesn't increase as much. Less surface area per volume means you can retain heat better. And then that second, three-foot-long horn on the woolly rhino, it was wide and flat.
Mr. WANG: The animal actually used it to sweep snow.
JOYCE: Why sweep snow?
Mr. WANG: So that they can get at the vegetation below the snow cover.
JOYCE: Wang says he has Tibetan fossils of an ancient blue sheep - technically a goat but never mind - that eventually became another citizen of the Ice Age. So Wang thinks the Plateau was a sort of evolutionary cradle for cold weather animals. When the rest of the world eventually iced up, they moved out of Tibet and took over.
Anthony Barnosky is a paleontologist at the University of California at Berkeley, and he says even now, these isolated cradles are important for evolution.
Dr. ANTHONY BARNOSKY (Paleontologist, University of California): The interesting thing is, on earth today, we have biodiversity isolated in certain spots, and you just never know which of those isolated places is going to be the cradle of evolution for the next big environmental change coming down the pike.
JOYCE: The only problem is, to be ready, you have to know what the next environment will be like, or just be very lucky. The research appears in the journal Science.
Christopher Joyce, NPR News.
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