Polar Bear Information and Facts

Polar bear’s scientific name, Ursus maritimus, means “sea bear” in Latin

Polar bears are called Nanuuq by Eskimos

Other names they are known by include ice bear and isbj

Polar bears are one of the largest land carnivores

They exhibit sexual dimorphism, where male polar bears can be two to three times larger than female polar bears

Males range from about 8-10 feet in length, while females are generally 6-8 feet in length

Male polar bears can weigh up to three times as much as the females

Males are typically 550-1700 pounds, and females are 330-650 pounds

Polar bears probably evolved during the Pleistocene Era Splitting from brown bears in Asia only around 150,000 years ago

The oldest known fossil of a polar bear is less than 100,000 years old

According to Guinness, the heaviest polar bear ever documented was shot in Alaska in 1960

Polar bears are extremely well-adapted to their arctic environment

They have the thickest fur of any bear species

The outer layer provides extra insulation and repels cold water and ice

The tubes trap air for insulation and also reflect all the visible wavelengths of light in their hollow airspace, which combine to make the fur look white, though it is in fact colorless

The white coloring provides excellent camouflage for the bears, allowing them to blend in with their snowy surroundings

Polar bears molt in the summer months and grow a new coat

They sometimes wash their fur in ice or snow during or after feeding

Underneath their fur, polar bears have black skin which absorbs the heat of the sun, and below the skin is a thick, 4-inch layer of blubber

This blubber layer is particularly beneficial while polar bears swim, keeping them warm in the cold water and increasing buoyancy

Polar bears also have fur on the bottoms of their paws, providing extra warmth and creating traction on the ice

The paws are broad to distribute their weight as they walk across ice and snow, and tipped with long, powerful claws to help grip the ice

Compared to other bears, the polar bear has an elongated body with a particularly long neck and a narrow skull

Large, flat, and partially webbed paws, functioning like oars, also help them navigate the water

Polar bears are classified as carnivores and are the most carnivorous member of the bear family

After catching a seal, polar bears will consume the fat and skin first, often leaving the rest of the meat for other animals like Arctic foxes, ravens, Arctic gulls, and smaller bears, to scavenge

The fat is eaten before the rest of the meat for several reasons

Not only is fat easier for the bears to digest, but it also contains more calories, which makes for more efficient eating

This allows the metabolism of the bears to function without the need to drink water, which they do not do

Polar bears require great amounts of energy to maintain their body temperature and must build up fat reserves to do that

Seals are optimal food sources because their blubber is so rich in calories and fat

Polar bears need to consume approximately 44 pounds of fat daily or a 121 lbs seal provides about 8 days’ worth of energy

Polar bears can eat 100 lbs of seal blubber in one sitting

Though polar bears are excellent swimmers, they rarely catch seals in open water and must employ a variety of hunting methods

The most common method they use is still-hunting, in which the bear waits motionlessly for hours, or even days, outside seal breathing holes for a seal to surface

When a seal does come to the surface, the bear bites the seal on the head and neck, flips it onto the ice with its claws, and drags it from the water

Polar bears may also stalk seals basking on ice edges, pouncing on them before they can return to the water

Polar bears also hunt seals at birthing lairs

After locating a lair, the bears stand on their hind legs for momentum and slam down their front paws, breaking through the roof to get to their prey

Polar bears are opportunistic hunters and will prey on whales caught in pack ice openings, or scavenge on beluga and bowhead whale, narwhal, walrus, seal carcasses

Polar bears have a keen sense of smell

They can smell a carcass or a live seal from many miles away

They adopt a submissive position by laying on or close to ground, circle around carcass, and touch the nose of the bear who ‘owns’ the carcass

Polar bears depend heavily on pack ice or ice floes either far out at sea, or at or near continental or island coastlines

They prefer areas where continual wind and water currents cause the ice to undergo a cycle of melting and refreezing, preventing it from completely and permanently solidifying

These areas have high numbers of seals, polar bears’ preferred food source

Though polar bears spend time on land, especially during the summer months, they live predominantly out on the ice, following the seals, sometimes finding themselves hundreds of miles from land

Arctic air temperatures are -29 F on average in the winter and 32 F on average in the summer

Ocean temperatures in the arctic drop to 29 F in summer and 28 F, the freezing point of seawater, in winter

Polar bear home ranges are typically larger than those of other mammals due to the seasonal and yearly transience of the ice

The prevalence of food, mates, and dens within a particular area may also determine the size of a home range

Bears near the Canadian Arctic Islands have relatively small home ranges—19,305-23,166 sq miles

Bears that live in proximity to Bering and Chukchi Seas often have larger territories that can be up to 135,135 sq miles

Polar bears do not mark their territory or aggressively guard it

Polar bears are found throughout the Northern Hemispheric Arctic Circle along the north and northwestern coasts of Alaska, throughout Canada’s north arctic islands down to its southern Hudson Bay area, Greenland, in islands off the coast of Norway, and along the northern coast of Russia

Scientists have identified 19 subpopulations in ice caps across the Arctic region

Polar bears reach maturity between the ages of 3 and 5 years

Females typically have their first litter at 5 or 6 while most males do not breed until 8 or 10

Female polar bears give birth every 2-3 years and have around five litters during their lifetime—one of the lowest mammalian reproductive rates

The mating season runs from late March through May Males travel great distances and have been known to follow a female for 62 miles to find a mate

A breeding pair stays together for a week and mates several times during that period

The polar bear gestation period is 8 months, though the development of the embryo is about 4 months

Females often refrain from mating if they do not have substantial food sources or the necessary fat reserves

Pregnant females must eat a great deal throughout the summer and autumn to prepare for hibernation; a pregnant female needs to gain around 441 lbs to sustain both herself and her cubs throughout her pregnancy

Cubs are born while the females are hibernating

Their litter size can range from 1 to 4 cubs but is typically 2

Within the first month of life, their eyes open, and within 2 months, they grow teeth and fur and begin to walk

Cubs weigh around 1 pound at birth but are nursed to a weight of 20-30 pounds by the time they leave the den in March or April

Maternity dens are typically dug in south-facing snowdrifts on thick stable pack ice at sea, or on hilly and mountain slopes on land

Dens usually contain an entrance tunnel leading into several concave rooms with an inside temperature up to 40 degrees warmer than the outside, maintained by body heat and insulation from the snow

In the weeks immediately following hibernation, mothers and cubs continue to stay close to the den as the cubs acclimate to the outside world

When they are ready, they leave the den and travel toward the edge of the sea ice, where the thin and hungry mother bears that have not eaten for months immediately begins to hunt, giving her cubs a first lesson in how it’s done

Cubs remain with their mothers for just over 2 years, denning with her for one or two more winters

The family breaks up after 24-28 months, after which females breed again and the now independent cubs enter what is called the sub-adult stage, which continues until they reach maturity at 5-6 years

Unlike other bears, all polar bears do not hibernate for the winter – only pregnant female polar bears do

They do not urinate or defecate, their heart rate slows slightly, and their body temperature either remains the same or drops one or two degrees for the duration of their months-long sleep, which is easily disturbed

Pregnant females wake for the birth of their cubs in the den, and for necessary elements of their care

Polar bears generally lead solitary lives, with the exception of mothers raising cubs and breeding pairs

Mothers are highly affectionate and attentive to their cubs, and cubs spend much time playing, chasing and tackling one another

Many bears do congregate at large kill sites, such as areas with large whale carcasses

And some adult and sub-adult males, however, sometimes form friendships which can last weeks or sometimes even years

These males may travel, feed, and play-fight together

Though polar bears are not territorial, aggression occurs between males competing for breeding females, in mothers protecting cubs, and in cases where bears may try to steal or scavenge food from another’s kill

Polar bears can communicate using a broad variety of vocalizations, such as growling, hissing, panting, snorting, teeth champing, whimpering, braying, lip-smacking, and chuffing

Cubs typically vocalize more than adults, and mothers communicate extensively with their cubs

In addition to vocalizations, she may use her muzzle, paws, and body to comfort, protect, or discipline her cubs

They gently touch the face and neck of the other bear with its nose or mouth

Once play-fighting is initiated, both bears stand on their hind legs and try to push each other over with their paws

Polar bears can travel thousands of miles yearly, swimming and walking, following the pack ice to hunt

Polar bears are excellent swimmers

Some have been observed swimming 200 miles from land

They swim with their head and some of their back above the water in a doggy paddle style

Polar bears walk in a distinctive swinging gait

Like humans, they walk on the soles of their feet, touching the ground with their heels first

Like other bears, they can stand and walk on their two hind feet for brief amounts of time

Polar bears in the wild can live between 20 and 25 years

Polar bears vitally depend on the ice, so their biggest threat is global warming and melting sea ice

As the ice disappears, polar bears must travel longer distances across open water to reach prey, risking drowning in the ocean while searching for the next ice floe on which to hunt or rest

The melting sea ice also affects seal population numbers, jeopardizing the polar bears’ major food source

Melting ice and shifts in climate have caused grizzly bears to move more and more into arctic tundra habitats in Canada which can lead to grizzly-polar competition for resources

Poaching and unregulated hunting further decrease polar bear populations

Polar bears drawn to human settlements by garbage or nearby animal carcasses are often killed

The polar bear is classified as Vulnerable on the International Union for Conservation of Nature (IUCN) Red List

**This post is an update from a previous polar bear fact sheet from NATURE

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