Polar Bear Fact Sheet
Polar Bear Fact Sheet
Aug 28 2005, 05:02 PM
Group: TREC Team
Joined: 27-April 05
Member No.: 10
•The largest bear species
•Pelage entirely white, cream-colored, or yellowish white
•Male much larger than female
•Circumpolar distribution in Arctic regions
•Global population about 20 000 to 40 000
•Length: (Male 2.6m - 8'6") (Female 2.1m - 6'11")
•Weight: (Male 1800lb - 800kg) (Female 660lb - 300kg)
•Weight at birth: 1.3 lb (0.6kg)
•Life span: (Male 29 years) (Female 32 years)
The polar bear is the largest land carnivore in North America and the top predator in the arctic marine ecosystem. Polar bears are also known in Norway and Germany as "ice bears." The ears are smaller than those of other bears; an adaptation to the cold arctic environment and the neck is longer and lacks the shoulder hump that is characteristic of other bears. Polar bears have partially webbed forepaws, an adaptation for swimming. The five digits on each paw are armed with strong retractable claws. Males are twice as big as females. The polar bear is buoyed in water with its head held high. It is a strong swimmer. Insulation is provided by both fur and fat. The long guard hairs from a watertight outer coat over a soft and fluffy undercoat which traps a layer of air against the skin allows it to swim well without getting wet to the skin. Once out of the water a quick shake leaves the outer coat almost dry. The guard hairs are hollow, air filled and very strong. Whatever color polar bear fur appears, the individual hairs are actually colorless. The hollow hairs are thought to function like optical fibers, transporting the sun’s radiation energy to the bears black skin, which stores the heat.
Polar bears occupy fast ice and pack ice habitats where their main pray, Ringed Seals, occur year-round. Females travel with their cubs for two to 3 years. Great endurance walkers and swimmers, these bears make seasonal migrations of between 1200 and 2500 miles across the ice and can swim 60 miles (100 km) in open water. They are fast runners, reaching speeds of 25-30 miles per hour. Females use dens throughout the winter and both males and females may construct dens for short term shelters to conserve energy when food is scarce.
Mating occurs from March to May. Gestation lasts 6-8 months. In November/December pregnant females dig maternity dens. Females give birth to up to 3 cubs in December or January. In spring, the leave the dens when the cubs are able to travel over the ice. Cubs are weaned at about 2.5 years.
The primary food is the blubber (fat) of Ringed seals. Summer is lean time for the polar bears. Deprived of the ice they come ashore. At this time they are very hungry and dangerous. They need to be taken seriously. People do get eaten. Indeed, researchers in areas known for polar bears are required by law to carry a suitable fire arm at all times in the field.
The polar bear is a protected species. The polar bear population is affected by hunting, oil exploration, shipping, pollution and global warming. The polar bear is at the top of the arctic ecosystem, and whatever goes wrong at the lower levels of the system will be reflected in the polar bear’s condition- a natural indicator for monitoring the marine ecosystem and our ability to prevent the destruction of the Arctic.
Interesting fact: Inuit hunters seem to have copied certain of the polar bear’s techniques for stalking and capturing prey.
Ovsyanilov, N (1998). Polar Bears. Sillwater, MN: Voyageur Press.
Soper, T (2001). The Arctic-A guide to coastal wildlife. Travel guides UK: Globe Pequot Press.
Aug 29 2005, 10:48 PM
Joined: 29-April 05
From: Fairbanks, Alaska
Member No.: 13
For additional information about Polar Bears, you might try this website with the U.S. Fish and Wildlife Service, Office of Marine Mammals Management:
Be sure to also check out their "related sites" which provides weblinks to various international polar bear organizations.
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