Habitat
Polar bears are found throughout the Arctic on frozen seas and near coasts. They share this habitat with indigenous peoples, and animals such as ringed seals, Arctic foxes, narwhal, beluga whales, and millions of migratory birds. There are believed to be at least 22,000 polar bears worldwide, and about 60 per cent of them live in Canada. Tracks have been reported as far north as the pole, but scientists believe few bears travel beyond 82° north latitude, as the northern Arctic Ocean has little food for them.

Polar bears spend much of their time at or near the edge of the sea ice; this is where they are most likely to find food. As the southern edge of the Arctic ice cap melts in summer, some bears follow the retreating ice north to stay close to seals and other prey. Other bears spend their summers on land, living off body fat stored from successful hunting in the spring and winter. When the ice returns in the autumn, the bears leave land to resume life on the sea ice.


Diet
A healthy diet for a polar bear consists of about 2kg of fat per day. The ringed seal has a high body fat content and is the polar bear's primary prey. It provides lots of energy which is especially important for hungry mothers and their growing cubs. Polar bears eat more between late April and mid-July when prey is abundant. They need to build up their body weight to survive the ice-free season, which can last three or four months, when food is hard to come by.

When conditions are icy, seals must come up from the sea to breathe at holes in the ice. Polar bears like to sit and wait by these holes so they can catch the seals as they emerge. The bears often spend several hours lying completely still on their stomach and chest with their chin on the ice, waiting patiently for a seal to appear.

Polar bears also hunt bearded and harp seals. When seals are not available they will prey upon young walrus and beluga whale, narwhal, fish, and seabirds and their eggs. Near human settlements, polar bears have been spotted foraging for food in rubbish dumps.


Family life
Polar bears are usually solitary animals, but in southern areas of the Arctic they gather together on land during the ice-free season to breed. Breeding pairs remain together for about a week then separate. The most constant social interaction occurs between mothers and cubs. In the late autumn, pregnant bears dig dens in deep snowdrifts on land, while the rest of the population remains active on the ice throughout the winter.

After about two months, the cubs are born in the den. There are usually two cubs, each about the size of a guinea pig and weighing around 600g. Cubs are nursed in the den on fat-rich milk until they weigh about 10kg, and are large enough to venture onto the sea ice in March or April. They usually stay with their mother for about two and a half years before striking out on their own.


Current threats & problems

Large carnivores are sensitive indicators of the health of an ecosystem, so polar bears are studied to gain an understanding of what is happening throughout the Arctic. A polar bear at risk is often a sign of something wrong somewhere in the Arctic marine ecosystem.

Climate change
The Intergovernmental Panel on Climate Change has confirmed that human-induced climate change is a reality. In the Arctic, climate change impacts will be seen earlier and more dramatically than elsewhere in the world. In the southern range of polar bears sea ice is now melting earlier in the spring and forming later in the autumn. The polar bears need the ice to hunt and when the icy season is short it is hard to put on enough weight to survive the ice-free Summer and Autumn months. Most polar bears suffer decreased body condition which can lead to lower reproduction rates and even the disappearance of polar bears from some areas. This situation could extend to other parts of the Arctic should climate change go unchecked.

Toxic chemical pollution
The image of the polar bear living in a pristine, unpolluted, frozen environment
is unfortunately a misleading one. Recent scientific research shows that, in some areas, polar bears are exposed to high levels of poisons and pollutants. Persistent organic pollutants (POPs) include a wide range of poisonous substances that remain in the environment for a long time. These substances become concentrated in parts of the Arctic, owing to the direction of prevailing winds and ocean currents.

As a top predator, the polar bear takes on high levels of such pollutants through its food. Bears with high levels of some POPs have a low level of vitamin A, thyroid hormones, and some antibodies. These are important for a wide range of biological functions, such as growth, development, reproduction, behaviour, and the ability to fight off diseases.

Oil exploration
Oil exploration, extraction, transportation, and processing in the Arctic affect the polar bear and its habitat in many ways. There are already large oil operations in the Arctic, and the oil and gas industry is set to expand in the years ahead.

Companies searching for or extracting oil can cause huge disturbances to the polar bear's environment such as explosions, construction work, roads and general contamination of the environment when oil is spilt and other toxic chemicals are discharged.

The insulating effect of polar bears' fur is reduced if they come into contact with spilt oil causing the bear to use more energy to keep warm. Using more energy causes the bear to lose weight faster in the food-scarce season and may even lead to starvation. If polar bears ingest oil, through grooming, scavenging or eating contaminated prey, they can suffer liver and kidney damage.


Hunting
There are estimated to be at least 22,000 polar bears worldwide, living in 20 separate populations. The general status of the polar bear is currently stable, though there are differences between populations. Polar bears are currently classified as "lower risk/conservation dependent" on the IUCN Red List of Threatened Species.

The International Agreement on the Conservation of Polar Bears allows for the killing of polar bears for use by local people using traditional methods and exercising traditional rights. Though traditional hunting by local communities is sustainable, the IUCN Polar Bear Specialist Group documents that, both historically and currently, the main threat to polar bears is still excesive hunting. Today, legal hunting of polar bears by non-native sport hunters is found only in Canada .

The community itself decides what proportion of the quota it has been issued will be used for sport hunters. In the areas that lack monitoring, such as Russia, little information is available on current hunting practices. Since it is not known whether killing polar bears is balanced against the growth of a known population in such areas, there is reason for concern regarding the sustainability of these practices.


What WWF is doing

WWF has been working for more than a decade to reduce the threat of chemical contamination to wildlife and humans. WWF has actively pressed ministers of the world's governments to raise awareness about hazardous man-made chemicals.

We need your help now to convert that awareness into strong legislation for a healthier future. Visit our Chemicals and Health Campaign website to find out how you can help.

WWF is working hard to reduce CO₂ emissions in industrialised countries, by campaigning to change legislation and so remove barriers to the development of forms of renewable energy and allow improvements in energy efficiency.

In developing countries we are trying to reduce the ratio of CO₂ emissions to energy requirements, and to help those regions of the world that are most at risk from the impacts of climate change.