polar bears

Polar bears are well adapted to severe cold. Winter temperatures in the far north often plunge to -40° F or -50° F and can stay that way for days or even weeks. A thick layer of blubber (up to 4.5 inches thick) provides polar bears with such excellent insulation that their body temperature and metabolic rate remain the same even at -34°F. On bitterly cold days with fierce winds, polar bears dig out a shelter in a snow bank and curl up in a tight ball to wait out the storm. Polar bears have more problems with overheating than they do with cold. Even in very cold weather, they quickly overheat when they try to run.
The polar bear's main prey is the rin...