Smithsonian National Museum of Natural History, North American Mammals
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Ursus maritimus

Polar Bear

Order: Carnivora
Family: Ursidae

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Conservation Status: Vulnerable.

Polar Bears prey mostly on Ringed Seals. In the spring, the pups are easy prey. They also hunt Bearded and Harp Seals, Walruses, Beluga, Narwhals, and sea ducks, and very occasionally eat small amounts of plant matter. They travel long distances to stay with pack ice, and fast for long periods of time if food is not available. In Hudson Bay, the ice melts by late July and the bears fast until November, when it freezes again. They do not drink water or urinate the whole time. Pregnant females, who enter dens to give birth, continue fasting for another four months, living only on stored fat for eight months. Cubs are born in December, and are ready to follow their mother out of the den and learn to hunt by March or April. They are independent when they are about two-and-a-half years old, at which point the female mates again.

Also known as:
White Bear, Ice Bear, Nanuk

Sexual Dimorphism:
Males are about twice the size of females.

Range: 2,300-2,600 mm males; 1,900-2,100 mm females

Range: 400-600 kg males; 175-300 kg females (350-500 kg when pregnant)


Phipps, C.J., 1774.  A voyage towards the North Pole, p., 185.  J. Nourse, London, 253 pp.


Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Ursus maritimus

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