Bears living on the Admiralty, Baranof and Chichagof Islands in Alaska are the result of mating between brown and polar bears just several thousand years ago, complicating attempts to determine the origins of polar bears, according to a study published in the journal PLoS Genetics. The findings contradict past studies that found the two species diverged 4 million years ago. "If we really want to understand the evolution of brown bears and polar bears, we should ignore" the Alaskan islands' bears, said Beth Shapiro, co-author of the study. "They are a special case and they're not going to tell us anything about the origin of the polar bear."
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