The polar bear is the most carnivorous of all members of the bear family, and most of its diet consists of ringed and bearded seals. The Arctic is home to millions of seals, which become prey when they surface in holes in the ice in order to breathe, or when they haul out on the ice to rest Polar bears hunt primarily at the interface between ice, water, and air; they only rarely catch seals on land or in open water.

The polar bear's most common hunting method is called still-hunting. The bear uses its excellent sense of smell to locate a seal breathing hole, and crouches nearby in silence for a seal to appear. When the seal exhales, the bear smells its breath, reaches into the hole with a fore paw, and drags it out onto the ice.

The polar bear kills the seal by biting its head to crush its skull. The polar bear also hunts by stalking seals resting on the ice. Upon spotting a seal, it walks to within 100 yd (91 m), and then crouches. If the seal does not notice, the bear creeps to within 30 to 40 feet (9.1 to 12 m) of the seal and then suddenly rushes forth to attack. A third hunting method is to raid the birth lairs that female seals create in the snow.

A widespread legend tells that polar bears cover their black noses with their paws when hunting. This behaviour, if it happens, is rare — although the story exists in native oral history and in accounts by early Arctic explorers, there is no record of an eyewitness account of the behaviour in recent decades.

Mature bears tend to eat only the calorie-rich skin and blubber of the seal, whereas younger bears consume the protein-rich red meat. Studies have also photographed polar bears scaling near-vertical cliffs, to eat birds' chicks and eggs.

For sub-adult bears which are independent of their mother but have not yet gained enough experience and body size to successfully hunt seals, scavenging the carcasses from other bears' kills is an important source of nutrition. Sub-adults may also be forced to accept a half-eaten carcass if they kill a seal but cannot defend it from larger polar bears. After feeding, polar bears wash themselves with water or snow.

The polar bear is an enormously powerful predator. It can kill a full grown adult walrus, although this is rarely attempted as a walrus can be more than twice the bear's weight, and has up to three feet long ivory tusks that can be used as formidable weapons.

Most attacks on walruses occur when the bear charges a group and either targets the slower moving walruses, usually either young or infirm ones, or a walrus that's injured in the rush of walruses trying to escape. They will also attack adult walruses when their diving holes have frozen over or intercept them before they can get back to the diving hole in the ice. Since attacks on walruses tend to be an extremely protracted and exhausting venture, bears have been known to abandon the hunt after making the initial injury.

Polar bears also have been seen to prey on beluga whales, by swiping at them at breathing holes. The whales are of similar size to the walrus and nearly as difficult for the bear to subdue. Polar bears very seldom attack full-grown adult whales.

Most terrestrial animals in the Arctic can outrun the polar bear on land as polar bears overheat quickly, and most marine animals the bear encounters can out swim it.

In some areas, the polar bear's diet is supplemented by walrus calves and by the carcasses of dead adult walruses or whales, whose blubber is readily devoured even when rotten.

With the exception of pregnant females, polar bears are active year-round, although they have a vestigial hibernation induction trigger in their blood. Unlike brown and black bears, polar bears are capable of fasting for up to several months during late summer and early fall, when they cannot hunt for seals because the sea is unfrozen.

When sea ice is unavailable during summer and early autumn, some populations live off fat reserves for months at a time. Polar bears have also been observed to eat a wide variety of other wild foods, including muskox, reindeer, birds, eggs, rodents, shellfish, crabs, and other polar bears. They may also eat plants, including berries, roots, and kelp, however none of these are a significant part of their diet. The polar bear's biology is specialised to require large amounts of fat from marine mammals, and it cannot derive sufficient caloric intake from terrestrial food.

Dangerous diet!

Being both curious animals and scavengers, polar bears investigate and consume garbage where they come into contact with humans.

This means that Polar bears may attempt to consume almost anything they can find, including hazardous substances such as Styrofoam plastic, car batteries, ethylene glycol, hydraulic fluid, and motor oil.

To reduce the incidence of poisoning, the municipal dump in Churchill, Manitoba was closed in 2006 to protect bears, and waste is now recycled or transported to Thompson, Manitoba.

Polar Bear Factoid

The Inuit (Eskimo) people of North America and Greenland hunt the polar bear for its meat and fur. However, they cannot eat its liver. Why? Because its holds such a high content of vitamin A, polar bear liver is poisonous to humans!

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