Polar bears are the largest land carnivores in the world, rivaled
only by the Kodiak brown bears of southwestern Alaska. Polar bears
sit at the top of the food chain in the biologically rich Arctic.
The most carnivorous of the bear species, polar bears feed primarily
on the fat of ice-dependent seals. The remains of these seals provide
food for many other Arctic wildlife species, giving polar bears
a vital role in their ecosystem.
Polar bears are marine mammals, and spend much of their time
on Arctic sea ice. Many adaptations make polar bears uniquely suited
to life in icy habitats. Their fur is thicker than any other bears
and covers even their feet for warmth and traction on ice. A thick
layer of blubber beneath their fur provides buoyancy and insulation.
The long neck and narrow skull of the polar bear probably aid in
streamlining the animal in the water while warming the air that
they breathe, and their front feet are large, flat and oar-like,
making them excellent swimmers.
Did You Know?
Polar bears have black skin to absorb heat and white
fur to blend in with their environment.
Polar bears feed almost exclusively on ringed seals and bearded
seals. They are also known to eat walrus, beluga whale and bowhead
whale carcasses, birds eggs, and (rarely) vegetation. Polar
bears travel great distances in search of prey.
The World Conservation Union (IUCN) estimates that there
are between 20,000-25,000 polar bears in the world.
Range & Habitat
Polar bears are only found in the Arctic. The most
important habitats for polar bears are the edges of pack ice where
currents and wind interact, forming a continually melting and refreezing
matrix of ice patches and leads (open spaces in the ocean between
sea ice). These are the areas of where polar bears can find the
greatest number of seals.
As the sea ice advances and retreats each season, individual
polar bears may travel thousands of miles per year to find food.
Polar bears are distributed throughout the Arctic region in 19 subpopulations,
including Alaska, Canada, Russia, Greenland and Norway.
Did You Know?
The polar bear is the largest and most carnivorous
member of the bear family.
Polar bears are highly dependent on older stable pack
ice in the Arctic region, where they spend much of their time on
the ice hunting, mating and denning. They are generally solitary
as adults, except during breeding and cub rearing. Polar bears are
strong swimmers, and individuals have been seen in open Arctic waters
as far as 200 miles from land, although swimming long distances
is not preferred since it requires so much energy for adults and
can be fatal to younger bears.
Unlike brown bears, males and non-breeding females do not hibernate
in the winter.
Did You Know?
At birth, polar bear cubs are 12 to 14 inches long
and weigh around one pound.
Pregnant polar bears need to eat a lot in the summer
and fall build up enough fat reserves to survive the denning period.
They seek out maternity dens in October or November. Most maternity
dens are located on land where snow accumulates including along
coastal bluffs, river banks or pressure ridges on sea ice. Sows
give birth to usually 1 or 2 one-pound cubs and then nurse them
until they reach about 20-30 pounds before emerging from the den
in March or April. The young are born from November through January
while the mothers are hibernating. Cubs will remain with their mothers
for a little over 2 years. Female polar bears can produce five litters
in their lifetime, which is one of the lowest reproductive rates
of any mammal.
||Late March - May
||About 8 months with delayed implantation
||1 - 4 cubs; though 1 or 2 cubs is most common