Are Polar Bears Victims of the New Cold War?

This 2004 incident, reported by Steven Amstrup of the U.S. Geological Survey's Alaska Science Center, was the first report of polar bear cannibalism in two decades of study in the Beaufort Sea area of northern Alaska, and in 30 years of studies in northwestern Canada. Since then, Amstrup has documented two additional cases.

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Some prominent researchers suspect that changes in the climate are a leading threat to polar bear survival. Polar bears are especially vulnerable to rising Arctic temperatures because they hunt, mate and usually make their dens on sea ice. "There is no evidence they can survive on land without sea ice," Williams said.