Polar bears are among the largest land carnivores. Adult male polar bears, called boars, weigh from 350 to 650 kg (772-1,433 lb.) and are about 2.5 to 3 m (8.2-9.8 ft.) long. Adult female bears, called sows, weigh from 150 to 250 kg (331-551 lb.) and are 2 to 2.5 m (6.6-8.2 ft.) long.

Adult polar bears need an average of 2 kg (4.4 lb.) of fat per day to maintain their weight. Their diet includes seals, walruses, whales, fish, and vegetation.

Adapted for the cold, polar bears have a thick fur coat. The coat can vary from pure white to creamy yellow to light brown, depending upon season and angle of light. A polar bear’s black skin absorbs heat from the sun, helping it stay warm.

Polar bears are strong swimmers, paddling dog-style with their front paws while holding their hind feet and legs flat like rudders. Scientists have tracked polar bears swimming continuously for 100 km (62 mi.).

Polar bear cubs are born in a den from November through January. At birth, cubs weigh about 454 to 680 g (16-24 oz.) and are about 30 cm (12 in.) long.

They are born helpless with their eyes closed, and appear hairless because of their very fine fur. Cubs open their eyes within the first month, and begin walking at two months. Cubs emerge from the den when they are four to six months old. By eight months, they weigh more than 45 kg (99 lb.).

Polar bears at zoological parks provide opportunities for the public to learn about these animals and how human activities may impact their survival. Scientists and specialists study polar bear biology, including polar bear reproduction, birth and care of young, and communication.