POLAR BEARS Made by : Carina Alvarado

Basic information on Polar Bears  The polar bear is a bear native to the Arctic Ocean and its surrounding seas. The world's largest predator found on land, an adult male weighs around 300–600 kg (660–1320 lb), while an adult female is about half that size. Although it is closely related to the brown bear, it has evolved to occupy a narrow ecological niche, with many body characteristics adapted for cold temperatures, for moving across snow, ice, and open water, and for hunting the seals which make up most of its diet.As it can hunt consistently only from sea ice, the polar bear spends much of the year on the frozen sea, although most polar bears are born on land. bearArctic Oceanbrown bearecological nicheseals sea icebearArctic Oceanbrown bearecological nicheseals sea ice  Polar bears are the largest land carnivore.  2. Male polar bears (boars) grow two to three times the size of female polar bears (sows). Boars weigh about 350 to more than 650 kg (772-1,433 lb.) and are about 2.5 to 3 m ( ft.) long (Stirling, 1988).  3. Sows weigh about 150 to 250 kg ( lb.) and are about 2 to 2.5 m ( ft.) long. Pregnant females can weigh as much as 500 kg (1,102 lb.) (Stirling, 1988).  4. The largest polar bear ever recorded was a male weighing 1,002 kg (2,209 lb.) and measuring 3.7 m (12 ft.) long (Domico, 1988).

Adaptations or something unique about Polar Bears  Polar Bear adaptation to the cold and unforgiving Arctic climate is one of nature's mysteries. The shifting sea ice, where polar bear live, is one of the unkindest and grimmest climates in the world. It's only in recent evolutionary period that bears adjusted to arctic sea life. It commenced during the Ice Age, in the northern seas, when the seals needed to breathe and reproduce on the water's surface. From this, the seals became a rich year-round food source within reach of a population of brown bears, who then began to inhabit the ice, developing into something similar to the polar bear of today, around 100,000 years ago.  Weighing around 330 to 1,760 pounds, the length of the polar bear's body is about 6.6 to 10 feet. The male body is generally larger than the female. The polar bear, similar to the brown bear, is heavy and stocky. It has an long neck and small head. Its fur, normally white, occasionally appears yellow, due to oxidation.  A polar bear has black skin, which aids it's adjustment to the Arctic temperature, absorbing and holding heat from the sunlight. It is definitely well dressed for the weather with a layer of fat more than 4 inches thick, providing efficient insulation. The dense fur on its feet (its foot is about 9 inches wide and 12 inches long) allows for warmth and traction. As each foot is so huge, it acts as a functional snowshoe.  It adjusts well to swimming with its broad forepaws that serve as paddles and when swimming underwater it lays the small ears flat for protection, and its nostrils close under water. It paddles at about 6 and one-half miles per hour --paws only, hind paws trailing--and can stay submerged for about 2 minutes. The hairs of its waterproof coat are hollow which is a good insulator and increases the bear's buoyancy when swimming.  A polar bear has a keen sense of smell, sensing prey at a distance of about 20 miles. Although little is known about its sense of touch (its eyesight and hearing is acute), a polar bear is able to manipulate various objects with surprising dexterity.  With canine teeth larger and malariform teeth sharper than those of different bears, the polar bear is the most carnivorous North American bear.  A polar bear inhabits Arctic islands, sea ice, and water and continental coastlines. It favors the sea ice habitat, with water channels or cracks through the ice, next to continental coastlines or islands. A lot of polar bears spend part of the year on land, although in warmer climates a bear might become isolated. Most pregnant females spend the autumn and winter on land in maternity dens.  A polar bear journeys throughout the year within individual home ranges, which are likely to be larger than for other mammal species because of the shifts in sea ice from year to year and even season to season. Small home ranges (19,000 to 23,000 miles) can be observed near Canadian Arctic Islands, while bigger home ranges can be viewed in the Bering or Chukchi Sea areas. The polar bear remains in the general area during the same season. A polar bear can travel 19 miles or more per day for several days, although some are capable of much more than that. One can only hope that polar bear adaptation will carry on, as their habitat area shrinks and the pressures of civilization continue to encroach on the the natural homes where the polar bear dwell.

Ancestors of the Polar Bears and living relatives The sea ice of the Arctic Ocean and the connected frozen seas is home to the largest and most predatory of the bear family. All bears alive today evolved 22 million years ago from a common ancestor — the Ursavus of Asia. Polar bears (Ursus maritimus) evolved from a group of brown [CL1] bears (Ursus arctos) over 200,000 years ago, which became isolated from other brown bear populations by glaciers, possibly in Siberia. It is easy to imagine the evolutionary change in brown bears that inhabited a northern coast during a climatic cooling period, when food as tempting as unwary seal pups can be found offshore.

Habitat the Polar Bears live in  Well Polar Bears live in the cold and windy northern arctic.The Polar Bears are also found throughout the circumpolar arctic on pack ice,along or near coasts,and on islands.Well Polar Bears share there habitat with indegenious people. Another thing is that Polar Bears