Friday, March 5, 2010

Polar Bears Aren't So Old

Polar bears are in real danger of becoming extinct if the planet warms much more. Which raises the question, how long have they been here? Because there have been times over the past few million years when the earth was much warmer than now.

Study of a 125,000-year-old polar bear fossil unearthed in Norway in 2004 has provided the first good information:
Our results confirm that the polar bear is an evolutionarily young species that split off from brown bears some 150,000 years ago and evolved extremely rapidly during the late Pleistocene, perhaps adapting to the opening of new habitats and food sources in response to climate changes just before the last interglacial period," says Charlotte Lindqvist . . . .
If correct, this means polar bears have survived at least one warm interglacial period, around 120,000 to 110,000 years ago, so perhaps they will make it through this one as well.

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