Polar Bears are pure white following
the spring molt, but their fur may become yellowish
in the summer. The head and body length of polar bears
range from 2,000-2,500 mm, tail from 76-127 mm. Females
weigh 150-330 kg, while females weigh 300-800 kg.
For a short distance, the Polar bear can outrun a
reindeer on land. In water, they can reach a swimming
speed of about 6.5 km/hr. The neck of a polar bear
is longer than that of other bears and their heads
are relatively smaller and flatter.
Bears feed primarily on ringed seals, which they catch
at or near their breathing holes in the pack ice.
The bear either remains still near a breathing hole,
or stealthily stalks its prey on the ice. In addition,
they eat carcasses of stranded marine mammals, small
land mammals, reindeer, fish, and vegetation. In the
waters they may swim among sea birds and catch them
as they sit on the water. Any individual bear may
make a winter den for temporary shelter during severe
weather, but only females, especially those that are
pregnant, generally hibernate for lengthy periods.
Most pregnant females hibernate on land in excavated
dens in the snow, usually on a steep slope. The sexes
usually come together only briefly during the mating
season, in March-June. Delayed implantation extends
the period of pregnancy to 195-265 days. The young
are born from November to January, while the mother
is in her winter den. Females give birth every 2-4
years. Litter size ranges from 2-4 pups, weighing
about 600 grms each. They weigh 10-15 kg when they
leave the den with their mother; they leave the mother
at 24- 28 months. Age of sexual maturity varies from
Bears (Ursus maritimus) are considered to be
marine mammals, as they are adept swimmers. Their
preferred habitat is on pack ice. It
may swim as far as 65 km across open water to reach
land or ice.
There are populations in Canada, Greenland,
USA (Alaska), Russia. Circumpolar
in the Arctic, S limits determined by ice pack.