The polar bear (Ursus maritimus) is always ready for cold weather. A close relative of the brown bear, this species has evolved specialized features to thrive in the Arctic. For example, a female polar bear’s milk is about 31 percent fat, making it the richest milk of any land mammal. It boosts their cubs’ growth, energy, and fat insulation, which helps the baby bears survive frigid temperatures.
via amnhnyc
