Polar+Bear

=Polar Bear=

Basic Statistics
Species name: //Ursus maritimus

Genus: //Ursus //Family: Ursidae Order: Carnivora Class: Mammalia Phylum: Chordata Kingdom: Metazoa //

Ecology
Polar bears generally live in the arctic tundra in and around the North Pole, where temperatures reach up to about 54 degrees Farenheit and rainfall is scarce. Polar bears live a nomadic lifestyle and depend on drifting pack ice to travel and hunt for food. The polar bear is an omnivorous consumer. Its diet includes: ringed seals, bearded seals, seabirds, reindeer, fish, and in the summer they eat berries and other vegetation. However, the polar bear is the largest land carnivore. The polar bear has the ability to swim 40 miles in open water in search of food. Because polar bears are so adapted to the icy environment in which they live, they don't need to drink water. Rather, they obtain liquid that their bodies require from the prey that they eat. Polar bears have no predators, except for humans that hunt them for their fur.

Physiology
Polar bears are either white, yellow, gray, or brown in color depending on the season. Although their fur is white, their skin is black which allows them to absorb heat from the sun. They have thick fur that covers their entire body which allows them to stay warm in harsh, cold climates and sheds water easily. The fur on the soles of their feet helps with balance and insulation. The blubber beneath their fur also provides insulation as well as buoyancy. They have large, paddle-shaped forefeet ideally for swimming. Polar bears also have long necks which allow them to glide smoothly through the water. Some may classify polar bears as a marine mammal because it spends much of its time in the water. Polar bears grow from about 6.5 feet to 8 feet. Males generally weigh about 661 - 1764 pounds, while females weigh about 331 - 661 pounds. The polar bear's white fur allows it to blend into the surrounding snow environment. Male and female polar bears normally live apart from each other, except during mating season from March to June. Polar bears are K strategists and have a gestation period of about 195 - 265 days (7-9 months). Female polar bears reach the reproductive age at about 3 years and give birth about every 2 to 4 years to one or two cubs. Polar bears do not hibernate. However,the female polar bears will den during pregnancy. At birth, polar bear cubs are blind and helpless and must have constant guidance from its mother for about 1 or 2 years. Polar bears may live up to 25 years in the wild. However, it is seen that polar bears live longer in captivity.

Although there are about 20,000 polar bears in existence, they are still an endangered species. Depletion of Polar Bears
For many years, polar bears have been hunted because every part of their body, except for the liver, was useful to the indigenous people living in the arctic. In Russia, polar bears were being commercially harvested for their fur.

Other Causes of Endangerment
Global warming is a major environmental concern all over the world. Not only does global warming affect people, it affects other organisms as well, including the polar bear. Because global temperatures are rising, arctic ice is melting away making it difficult for polar bears to hunt for food. Polar bears depend on drifting ice to hunt for seals. Also, with less ice floating in the water, polar bears would need to swim for greater distances which lessens their energy and could lead to drowning. If polar bears are unable to hunt because of this decrease in drifting ice, they would not be able to support themselves and their young. Pollution is also a major environmental concern. Because polar bears are tertiary consumers, the biomagnification of toxins accumulated from the seals and other organisms is higher, which puts the polar bear at a greater risk of poisoning.

Citation
· "Polar Bear." // Encyclopedia Americana //. 2010. Grolier Online. 4 May. 2010 < [] >
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