One specialized feature of polar bear anatomy is their development of webbed feet. Polar bears are highly efficient swimmers and are capable of traveling for hours at a time in the water without resting. Individual bears have been seen up to 200 miles out in the Arctic Ocean, using their large flat front feet as paddles.
Since polar bears may have to go extended stretches without eating, they have developed the ability to slow down their internal metabolism until they are able to locate food. However, they don't hibernate like some other species of bear. While a mother polar bear is in the den nursing her cubs, she will not eat, drink or defecate.
Another feature of the polar bear is its skin color. The bear's fur is white, but the skin underneath is black. The polar bear hunts seals and other Arctic wildlife primarily by using its highly developed sense of smell. According to LiveScience, an adult polar bear can determine the location of a seal's breathing hole in the ice from more than half a mile away. If a seal is up on the sea ice, a polar bear can smell it from up to 20 miles away.