Bear (Polar)

Polar bear: Ursus maritimus

Distribution: northern polar regions occurring in 5 nations - Greenland, Norway, Canada, United States, the former Soviet Union and also on Arctic sea pack ice usually within 300km of land. Some individuals wander up to 200km inland.

Habitat: favourite habitat is a combination of pack ice, open water and coastal land.

Description: coat colour varies from pure white to shades of yellow. Small ears; black eyes and nose.

Height: 1.6m to shoulder

Length: 2.2 - 2.5m.

Size of feet: 30cm long, 25cm wide.

Weight: male 400-500kg, female 300-350kg.

Life span: about 30 years.

Food: carnivorous, eating mainly the ringed seal, although small land mammals, carcasses of marine mammals and reindeer, berries etc, also form part of the diet.

The polar bear is one of the world's largest land carnivores and the largest of the bear family, although the North American grizzly bear and Kodiak bear can weigh more than a polar bear - sometimes over 900kg.

Polar Bear Habits

Polar bears are mostly solitary animals and are active at all times of year, always on the look-out for a meal. They are extremely strong and active and cover the ground quickly with long strides of their bowed legs. The soles of their feet are covered with hair to help them get a grip on slippery ground. Polar bears are also good swimmers using their front legs to propel them, their hind feet trailing behind. Keeping their eyes open and their nostrils closed, they dive beneath the surface and can stay under for up to two minutes at a time.

Hunting. One of the mainstays of the polar bear's diet is the ringed seal which it stalks across the ice or ambushes at a breathing hole. The white-yellow coat of a bear acts as camouflage against the snow-coloured background. The seal is killed by a blow from the bear's powerful paw. The fat and skin is usually eaten first and the meat left until last.

During the late summer and early autumn polar bears will search for walrus and whale carcasses (carrion) along the coastal areas. Sometimes ten or twenty bears may be feeding at a carcass. There is more open land at this time of year and the diet is more varied, including lemmings, Arctic foxes, ducks and their eggs. Polar bears, like most bears, will also feed on berries, toadstools, mosses, lichens, grasses, seaweeds etc.

Winter. Some bears spend both summer and winter along the lower edge of the pack ice, sometimes migrating from north to south as this edge shifts. Others move onto the land in the summer and spread out across the ice as it forms along the coast and between the islands during the winter.

Any polar bear may make a winter den for temporary shelter during severe weather, but only females, especially pregnant ones, hibernate for long periods. Most pregnant females do not spend the winter along the pack ice, but hibernate on land.

Breeding. Polar bears mate in the spring, particularly in April. During this time, the males wander over long distances, looking for females without cubs. Most females breed every three years when their young have left.

The female bear digs out her den during October and November, to a depth of 1 to 3 metres under the snow, often on a steep south-facing slope of a hill where northerly winds blow the snow into large piles. A den usually consists of a tunnel leading into a large chamber. The temperature inside the den can be 4.4 degrees Celcius warmer than the outside air temperature.

The cubs, usually two, are born in November or December, after a gestation period of 7 - 8 months, and are only the size of a rat, weighing 450 - 900g. To begin with they are blind and hairless. Feeding on their mother's rich milk, they grow very quickly and when they leave the den in March or April, they are about the size of a domestic cat. The cubs leave their mother in the third spring of their life.

Polar Bears and Man

Traditionally, the polar bear has been hunted by the Inuit (Eskimo) people of North America and Greenland for its fur and flesh, but it wasn't until Western man began hunting the bear for 'sport', often from aircraft, that the numbers of polar bears dwindled. Between 1965 and 1970 the population of polar bears was estimated at only 8,000 - 10,000 and it was classified as an endangered species.

Fortunately, in 1973, an international agreement banned the hunting of the polar bear, only the native Inuits being allowed to kill them. Since the ban, the polar bear population has steadily increased and the current population worldwide is now between 20,000 - 40,000. However, it is still an endangered animal and there are serious threats to the continued increase of the population; these are.......

Habitat destruction. The exploration and recovery of natural gas and oil in the Arctic Basin could destroy important polar bear habitat and food supplies if an accident should occur in the Polar sea - especially as the number of oil wells increases. The human population density may also increase as the development grows and this would increase the likelihood of human and polar bear conflicts.

Pollution. Toxic chemicals e.g. PCBs, dumped in the sea are transferred up the food chains and accumulate in polar bear body tissues. Scientists believe that these chemicals could affect the bears' reproduction and they may not be able to produce as many young as normal. There has been a noticeable increase in the level of organochlorines found in several polar bears in Canada.

Tourism. Tourist activity has increased in several areas which has led to accommodation building and the use of all-terrain vehicles and aircraft for aerial tours. This interference means humans come into contact with polar bears and can result in harassment, or even killing in self-defence. Indirectly it may also lead to the bears leaving their habitat to search for peace or abandoning their traditional dens.

The Future

In October 1988, a Polar Bear Specialist Group held a meeting in the USSR and recommended that all the countries within the polar bear's range should immediately get together to organise the co-ordination of research and management of their polar bear populations. The most serious threats to the future of the polar bear are destruction of their habitat, interference by tourists and pollution of the sea, and, if these are not restricted, the population of this great bear may once again begin to decline.

The data used in the last two sections, 'Polar Bears and Man' and 'The Future' was compiled and provided by The World Conservation Monitoring Centre under sponsorship by BT.