我想問有關北極熊有趣的資料

Fun Facts

* A polar bear's feet are webbed.
* No other four-footed animal can swim as fast as a polar bear.
* Polar bears sometimes slide slopes on their bellies.
* Polar bears can swim up to 50 miles without stopping.
* A fully grown polar bear's worst enemy is the killer whale.
* A polar bear's fur is white to keep itself camouflaged and its babies protected.
* Polar bears are the best hunters of the bear family.
* Polar Bears make a den only if the weather is worse than usual. A pregnant Polar Bear will also make a den.

http://en.wikipedia.org/wiki/Polar_bear#Evolution