Anatomy: Polar Bears are up to 10 feet (3 m) long and weigh about 1,700 pounds (770 kg); males are bigger than females. Polar bears have a small head, powerful jaws, and a black nose and tongue. They have a strong sense of smell. They have 42 teeth; the tail is small and flat. They have wide front paws with slightly webbed toes that help them swim. These bears paddle with their front feet and steer with the hind feet.

Fur and Skin: Polar Bears have two types of fur. They have thick, woolly fur close to the skin that keeps them warm. They also have hollow guard hairs that stick up and protect the bears from getting wet. These guard hairs are like drinking straws and are clear-colored (not white). The white-looking coat camouflages them well in the snow and ice. Under the fur, Polar Bears have black skin. They also have a thick layer of fat (up to 4 inches thick) under the skin that helps keep them warm.

Habitat and Range: Polar Bears live in icy Arctic areas of Alaska, Canada, Greenland, Norway, and Russia. They spend much of their time swimming in frigid seas.

Diet: Polar Bears are carnivores (meat-eaters) who frequently hunt and catch their prey in the water, often many miles from land. They are fierce predators who eat mostly seals (and some walruses and other marine mammals). A polar bear's stomach can hold up to 150 pounds. Polar bears don't drink water.

Reproduction: When pregnant, females (called sows) build snow dens in which they spend the winter; they usually give birth to twin cubs. Male polar bears (called boars) are active all year.

Classification: Kingdom Animalia (animals), Phylum Chordata, Class Mammalia (mammals), Order Carnivora, Family Ursidae (bears), Genus Ursus, species U. maritimus (meaning "sea bear").