A polar bear has black skin. On top of the black skin is white blubber. It weighs about 350-700 kilograms. When female polar bears are pregnant, they weigh about 500 kilograms. The largest polar bear recorded was 2,209 pounds. Scientists think that the brown bear evolved into the polar bear. But no one knows if brown bears really evolved into polar bears. It is a mystery. They have about 10 centimeters of blubber. Their blubber gets more yellowish has they grow. If the temperature is bigger than 10 degrees celcius, they will start to overheat.
