Their Skin is Actually Black: Although they look white, polar bear fur is translucent and pigment-free. It reflects visible light, which makes them appear white to our eyes. Underneath all that fur, their skin is jet black, which helps them soak up as much heat as possible from the sun.
They are Technically Marine Mammals: Because they spend most of their lives on the sea ice of the Arctic Ocean—and depend on it for their food—they are the only bear species to be classified as marine mammals, putting them in the same category as seals and whales.
They are Incredible Swimmers: Polar bears can swim for days at a time to get from one piece of ice to another. They use their large front paws like paddles and their back legs like rudders. One documented bear actually swam continuously for nine days, covering over 400 miles!
They Track Food with Their Feet: Polar bears have a highly developed sense of smell, but they also use "scent glands" in their paws. With every step they take, they leave behind a chemical trail that helps them communicate and track each other across the vast, frozen landscape.
Overheating is a Bigger Risk than Freezing: Polar bears are so well-insulated by two layers of fur and a thick layer of blubber (up to 10 cm thick) that they actually struggle more with heat than cold. They generally walk at a very slow, steady pace to avoid getting too hot.
