Did You Know That Polar Bears Aren't White?
Polar bear skin is black and the fur is not white at all. Each individual hair is a clear hollow tube called guard hair and looks white because of reflected light. The bear’s thin undercoat is not hollow. Like the guard hair it is colorless. This optical illusion provides good hunting camouflage in the snow and pack ice.
Polar bears fur is oily making it water repellent. This keeps the hairs from being matted down and makes it easy for bears to shake any water and ice free after swimming. Fur even grows on the bottom of their paws. This helps to protect against cold icy surfaces and creates good traction on ice. In addition, the soles of their feet have small bumps and cavities that create suction for added grip.
The polar bear has a subcutaneous fat layer much like blubber. This fat layer helps the bear retain body heat and its low density allows the bear to float in the water while swimming. Summer months are spent hunting food to build up that layer of fat to sustain the long Arctic winter nights. When a polar bear is at rest its internal temperature is a toasty 98 degrees Fahrenheit.
Another interesting adaptation is that polar bears have slightly webbed toes which help them swim. Polar bears have been observed swimming 100 miles at a stretch. Climate change is forcing the polar bear to swim farther and use more energy to hunt prey. As with Antarctica, the summer sea ice is breaking up earlier in spring and freezing later in the fall. Arctic ice has decreased by more than a half million square miles over the past 25 years.
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