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Polar Bear Hibernation

March 16, 2009

Polar bears don’t hibernate the way that other bears do.


Smarter than the average bear?…I’m Bob Hirshon and this is Science Update.
Listener Tom Wagner of Waterloo, Iowa, heard that polar bears can walk while they’re hibernating, and he wants to know how this is possible.

We consulted Steven Amstrup, senior polar bear scientist with the U.S. Geological Survey Alaska Science Center in Anchorage. He says unlike, say, black bears or grizzly bears, polar bears don’t hibernate in the classic sense. That is, they don’t sleep all winter in a den. Instead, they’ve evolved ways to conserve energy whenever they need to.

It’s almost like throwing a metabolic switch in their body that causes them to revert to a metabolism that’s similar to what it would be like if they were hibernating.

Amstrup says polar bears can do this at any time of the year, whenever food is scarce. If you’ve got a science question, call us at 1-800-WHY-ISIT. I’m Bob Hirshon for AAAS, the science society.