Polar bears (Ursus maritimus) is a bear native largely in the Arctic Circle covers the Arctic Ocean, its surrounding seas and surrounding land. This is the largest terrestrial carnivore and also the largest bear, together with omnivores Kodiak Bear, which is approximately the same size. A (male adult) pigs weighing around 350-680 kg (770 to 1.500 lb), while the sow (female adult) is about half that size. Although closely related to the brown bear, it has evolved to occupy a narrow ecological niche, with body characteristics adapted for cold temperatures, for moving on snow, ice, and open water, and for hunting the seals which make up the bulk of the diet. Although most polar bears born on land, they spend most of their time at sea. Their scientific name means "maritime bear", and is derived from this fact. Polar bears can hunt their preferred food of seals from the edge of sea ice, often living from fat recommendations when no sea ice is present.
Polar bears are classified as a vulnerable species, with eight of the sub-populations of polar bears nineteen decreased. For decades, large scale hunting of international concern for the future of the species but populations rebounded after controls and quotas began to happen. For thousands of years, the polar bear has been a key figure in the content, spiritual life, and culture of indigenous Arctic, and polar bears remains important in their cultures.
Polar bears are the largest terrestrial carnivore, being more than twice as large as Siberian tigers. It shares this title with the Kodiak bear. Adult males weigh 350-680 kg (770-1500 lbs) and measure 2.4 to 3 m (7.9 to 9.8 ft) long. The Guinness Book of World Records registered male on average has a body mass 386-408 kg (850-900 lb) and 133 cm shoulder height (4.36 ft). Adult females are about half the size of males and normally weigh 150-250 kg (330-550 lb), measuring 1.8 to 2.4 meters (5.9 to 7.9 feet) long. During pregnancy, however, they can weigh as much as 500 kg (1,100 lb). Polar bears are one of the most sexually dimorphic of mammals, exceeded only by the pinnipeds. Polar bears are the largest in the record, reportedly weighing 1,002 kg (2210 pounds), is a male shot at Kotzebue voice in northwestern Alaska in 1960. These specimens, when assembled, stands 339 cm (11.12 ft) high. Shoulder height adult polar bear is 122-160 cm (48 to 63 in).
Compared with its closest relative, the brown bear, the polar bear has a longer body and skull develop long and nose.As predicted by Allen's rule for northern animals, stocky legs and ears and a small tail. However, the feet are very large to distribute load when walking on snow or thin ice and provide propulsion when swimming, they may measure 30 cm (12 inches) in adults.
The pads of the feet are covered with small, soft papillae (bumps donation) which provide traction on the ice. Polar bear claws are short and stocky compared to the brown bear, perhaps to serve the needs of heavy container for holding prey and ice. Very raking claws below to assist in digging in the ice of the natural habitat. Study injury patterns in polar bear forelimbs found wound right next body to be more often than to the left, indicating, perhaps, right-handedness. Unlike the brown bear, polar bears in captivity are rarely overweight or very large, possibly as a reaction to the warm conditions of most zoos.
Polar bears remarkable isolated to 10 cm (3.9 in) of fat, skin, fur, they overheat at temperatures above 10 ° C (50 ° F), and almost invisible under infrared photography. Polar bear fur consists of dense underfur layer and the outer layer of hair caregivers, which appears white to tan but are actually transparent. Guardian hair is 5-15 cm (2.0 to 5.9 in) over most of the body. Polar bears gradually fall from May to August, but, unlike other Arctic mammals, they do not shed their mantle for a darker color to hide themselves in the summer conditions. The mantle cavity keeper polar bear hair was once thought to act as fiber-optic tubes to do light to dark skin, where it can be absorbed, however, this theory is disputed by recent studies.
White layer is usually yellow with age. When kept in captivity in warm, humid conditions, the fur may change color as the pale green algae that grows in the hair guardian. Males have significantly longer hair on their front legs, that long to bear the increase reached 14 years of age. Ornamental foreleg hair male is estimated to attract females, serving a similar function to the lion's mane.
Polar bears have a very well developed sense of smell, able to detect seals nearly 1 mile (1.6 km) away and buried under 3 ft (0.9 m) of snow. Hearing is about as acute as do humans, and its vision is also good at long distances.
Polar bears are good swimmers and individuals have been seen in open Arctic waters as far as 200 miles (320 km) off the ground. With body fat that gives buoyancy, fish swim in a dog paddle fashion using a large front legs for propulsion. Polar bears can swim 6 mph (9.7 km / h). When walking, the polar bear tends to have a slow gait and maintains an average speed of about 3.5 mph (5.6 km / h). When running, they can reach up to 25 mph (40 km / h).
Polar bear is often regarded as a marine mammal because of spending months at sea. The preferred habitat is the annual sea ice covering the waters over the landing continent and the Arctic inter-island archipelago. This area, known as the "Arctic ring of life", have high biological productivity compared to waters in the high Arctic. Polar bears tend to areas where sea ice meets water often, such as polynyas and leads (temporary stretches of open water in Arctic ice), to hunt the seals that make up most of the diet. Polar bears are therefore found primarily along the perimeter of the polar ice package, not in the Polar Basin close to the North Pole where the density of primary seal.
Annual ice contains areas of water that appear and disappear throughout the year as the weather changes. Seals migrate in response to these changes, and polar bears must follow their prey. In Hudson Bay, James Bay, and some other areas, the ice melts each summer actually (an event often referred to as "ice-floe separation"), forcing polar bears to go to ground and wait through the next months until freeze-up. In the Chukchi and Beaufort seas, polar bears backward every summer in more northern permanent ice freezes over the years.
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