Polar bears are the largest land-dwelling meat-eaters on Earth, with seals being their main source of food. Polar bears sit on the ice at a breathing hole, which is a spot where seals come for air, and wait for seals to surface. Sometimes they even swim underneath the ice to hunt. Occasionally, they eat whales that are trapped in the ice.
Polar bears live in cold environments, such as the Arctic, which is at the very top of the world. Because of the cold, polar bears have thick coats of fur. The top coat of fur looks white, but the individual hairs are actually hollow and transparent. This helps these animals to blend into the snow-covered landscape so that they can hunt. Beneath the transparent coat of fur, polar bears have black skin. This helps them absorb and retain any heat. The final layer of protection is thick blubber, which keeps heat trapped in the body and helps the bears float, especially important during swimming.
When polar bears are ready to give birth, the mothers dig dens in the snow and settle in for up to eight months. They do not leave the den, even to eat. The new babies, or cubs, are very small, weighing only about 1 pound.