polar bear (redirected from Polar-bear)

polar bear, large white bear, Ursus maritimus, formerly Thalarctos maritimus, of the coasts of arctic North America. Polar bears usually live on drifting pack ice, but sometimes wander long distances inland. They are powerful swimmers and may cross 20 to 30 mi (30–50 km) of water at a time.

The polar bear's body is long and streamlined, with a long neck and small head. Adult males are 7 to 9 1-2 ft (210–290 cm) long, stand 4 to 4 1-2 ft (122–137 cm) at the shoulder, and weigh 700 to 1,600 lbs (320–730 kg). Females are somewhat smaller. The extremely dense fur appears yellowish white but is in fact unpigmented. Unlike other bears, polar bears have hairy soles, which help them grip the ice. They may attain a running speed of 25 mi (40 km) per hr on ice.

Polar bears are omnivorous, but feed chiefly on marine animals such as seals and young walruses. Quite fearless, they will stalk any animal, including humans. They take advantage of carcasses left by hunters, and in summer eat vegetation on the shore. If food is scarce, their physiology can slow to a state known as walking hibernation.

Except for a brief courtship in summer, polar bears are solitary. Males and nonpregnant females are thought to wander all winter. A pregnant female makes a winter den in the snow; two tiny, helpless cubs are born in January and nursed in the den until March. They usually remain with the mother for about a year and a half, while learning to hunt.

Polar bears have been extensively hunted, especially by Eskimos, for fur, flesh, and ivory, and they have declined greatly in numbers. Although extremely dangerous to humans, they do well in captivity. They are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, family Ursidae.

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polar bear

Polar bear (Ursus maritimus).

(credit: Francois Gohier/Ardea London)

White semiaquatic bear (Ursus maritimus) found throughout Arctic regions, generally on drifting oceanic ice floes. A swift, wide-ranging traveler and a good swimmer, it stalks and captures its prey. It primarily eats seal but also fish, seaweed, grass, birds, and caribou. The male weighs 900–1,600 lbs (410–720 kg) and is about 5.3 ft (1.6 m) tall at the shoulder and 7–8 ft (2.2–2.5 m) long. It has a short tail. The hairy soles of its broad feet protect it from the cold and help it move across the ice. Though shy, it is dangerous when confronted.