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NWT
Polar Bear
Ursus
maritimus
Description
The
polar bear is one of the most recognized symbols of Canada’s north.
The world's largest land carnivore, a male polar bear can reach two
to three metres in length and weigh between 300-635 kilograms. Adult
females are smaller and can weigh between 150-300 kg.
These creamy white bears have long necks ending in narrow heads.
Their small eyes and ears, furry footpads and the thick layer of
fat under their skin help combat heat loss.
Distribution
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Polar
bears are found throughout the circumpolar north.
The majority of bears live on the sea ice around Canada’s
Arctic Islands.
In Canada, polar bears range from Labrador in the east to the
Yukon-Alaska border in the west.
They are found as far south as James Bay and as far north as
the tip of Ellesmere Island.
The only change in their North American range since
pre-Columbian times is a slight northward trend on the Labrador
coast. |
NOTE: Click on map for full view. Distributions are
approximate and not intended for legal use.
(JPG = 1584 KB) |
Population Size and Trends
The
world population of polar bears has been estimated at 22,000-27,000
animals.
These bears live in 10 to 15 separate sub-populations.
There is little or no contact between groups.
Canada has the largest population with an estimated 15,000 polar
bears. Three sub-populations, an estimated 3,000 bears, can be found along
the arctic coasts of the NWT.
The two largest of these populations are stable.
The third, a small population shared with Nunavut, is increasing in
size.
Habitat
Polar
bears are as comfortable on land as they are in water and are quite agile
in either environment. Polar
bears follow the ice. In
spring,
they can be found on the inhospitable, land-fast ice and coastal, pack ice
where they prey primarily on ringed and bearded seals.
Once the ice melts in summer, polar bears spend several months on
land. Reproductively active
females spend the winter on land where they construct dens by digging into
snowdrifts. Female polar
bears may return to the same denning area every year.
Males may also den but only during the harshest part of winter,
usually in late January and February.
Denning sites and spring feeding areas are important habitats for
polar bears.
Biology
Female
polar bears become sexually mature at age four or five while males mature
at age five or six.
On average, females give birth to two cubs.
Males take no part in raising the young.
Cubs stay with their mother for two years. This prevents her from
breeding more than once every three years.
Polar bears are truly carnivorous bears.
Meat makes up to 90 per cent of their diet.
Polar bears are solitary hunters and feed on seals, walrus, whales,
fish, and birds.
Limiting Factors
Polar
bear populations are mainly limited by human hunting. Given their low
reproductive rate, overhunting could severely deplete any of the 15
sub-populations. Because there is little contact between sub-populations, it
is unlikely that new bears would move into an overhunted area.
Therefore, it is important to carefully monitor each
sub-population. Changes in
the populations of seals and other prey items also affect polar bear
populations. Environmental
changes, such as a crude oil spill, could have a devastating effect on an
entire sub-population.
Protection
Polar
bears were internationally protected in 1976 under the International
Agreement on the Conservation of Polar Bears.
This agreement requires governments of all signing nations to
manage the bears according to
“sound conservation practices”.
In 1991,
COSEWIC designated polar bears as Vulnerable
because of the fragility of the arctic ecosystem where they are found.
Polar bear harvest is controlled by a strict quota system.
It limits the harvest of bears to 98 per year in the NWT.
Outfitted hunts for non-residents are included in the quota system.
These hunts play an important role in the economy of the region.
The average polar bear hunt costs $15,000.
About $10,000 remains in the local community.
In addition to quotas, the hunting of denning
bears or females with cubs is prohibited.
To ensure that mainly male bears are harvested, the hunting season
opens after the majority of females have denned for the winter.
This two-pronged approach of quotas and encouraging male harvests
helps maintain a healthy polar bear population in the NWT.
Recovery
The
polar bear populations in the NWT are considered stable and are not under
immediate threat.
Extensive research has been conducted on polar bears during the past two decades.
This research has increased our understanding of polar bear
population dynamics, the effects of pollution on polar bears and the
extent of their range and movements.
This data provides the basis for polar bear management programs in
the NWT.
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