Ursus maritimus
Tagged: animal, animalsPolar Bear
The polar bear i’s the largest carnivore on land. It may cover a range of over 100, 000 square miles (260,000 sq. km) in its lifetime. The polar bear is instantly recognizable by its white coat and huge bulk. Today the population is relatively stable. This magnificent creature is the world’s largest land-dwelling carnivore and evolved from the same common ancestor as the brown bear. The most striking feature of a polar bear is undoubtedly its thick coat. The hairs are virtually colorless; they lack any pigment, but tiny bubbles within the hairs create the impression of whiteness. There are two layers to the fur; a fleecy undercoat and an outer layer of longer guard hairs. The long hairs are hollow; they trap air inside their shafts, which provides insulation and helps keep the bear afloat when it is swimming.
Giant Hunters
White is the perfect color for an Arctic predator. There is little or no cover to conceal the animal from its prey, and it would be impossible for a polar bear to surprise an alert, intelligent creature like a seal were it not for its excellent camouflage. The bear’s black nose can give it away however, and there are stories of polar bears stalking seals while trying to cover their noses with a paw! Polar bears have excellent eyesight and a superb sense of smell. They can detect young ringed seals hidden in dens in the ice and use their massive, muscular forelegs to dig them out for an easy meal. The polar bear lives at the edge of the ice, where floes break away leaving cracks and channels of water. They are just as at home in the water as on land. Their big flat feet make efficient paddles: They swim well and are accomplished divers, able to stay underwater for up to two minutes at depths of 15 feet (4.5 m). They can leap from the water on to an ice floe over 6.5 feet (2 m) tall. True nomads, polar bears often hitch a ride on a drifting ice floe, traveling many miles at a time. They will occasionally dig a den in the snow to rest or wait out severe weather. Most of the time they are solitary creatures, but their vast ranges overlap, so from time to time they encounter other bears. They do not fight over territory, but scraps over food are common, and females with young are very aggressive. Most polar bears remain active throughout the year, even in the prolonged twilight of the Arctic winter. Pregnant females hibernate in dens dug into the snow. During this time a female’s body temperature is reduced by as much as 13°F (7°C), and her heart rate can fall as low as eight beats a minute, just enough to stay alive.
The young polar bears are born in midwinter, while the mother is in hibernation. Weighing only 24 to 28 ounces (600 to 700 g) at birth, they spend the next three months suckling rich, fatty milk from the still-sleeping mother-by March they can weigh as much as 33 pounds (15 kg). This puts a huge strain on the mother’s body, and by the spring she will have lost up to 40 percent of her body weight. Young bears stay with their mother for up to two and a half years, during which time she will teach them to swim, to hunt, and build snow dens. She will not breed while she is nursing; and when the time comes for her to mate, she will drive her cubs away. The adolescent cubs may stick together for a while, but soon go their separate ways. Polar bears were always scarce, and they suffered from severe, uncontrolled hunting during the 20th century. “International” animals, they wander widely across the Arctic wastes, where they face no real barriers, traveling from one nation’s part of the Arctic to another. Until the 1960s, when the five polar bear nations (Russia, Canada, Norway, Greenland, and the United States) signed a conservation treaty, it was difficult to protect them or to research population size. Since then numbers have increased, and today’s population seems stable, with most of the bears living in northern Canada. Controlled hunting is allowed in certain places, and the bears are also an important tourist attraction.
Polar bear
Ursus maritimus Family: Ursidae
- World population: 20,000-30,000
- Distribution: Polar regions of Russia, Norway (Svalbard and Jan Mayen), Greenland, Canada, and the U.S. (Alaska)
- Habitat: Arctic ice floes
- Size: Length: 8.2-11.5 ft (2.5-3.5 m); height at shoulder when on all fours: 42 in (107 cm); males larger than females. Weight: females 660 lb (300 kg); males 1,100-1,320 lb (500-600 kg)
- Form: A huge, stocky bear with proportionately small head, furry ears, short tail, and big, furry feet. The fur is thick and creamy-white to dirty yellow
- Diet: Mainly ringed and bearded seals and the occasional young walrus; will also eat carrion, eggs, rodents, berries, and just about anything it can find
- Breeding: Between 1 and 4 cubs (usually 2) born December-January
- Related endangered species: Asiatic black bear (Ursus thibetanus); Spectacled bear (Tremarctcos ornatus); sloth bear (Melursus ursinus)
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