Polar Bear

U.S. Fish & Wildlife Service
Polar Bear
Ursus maritimus
The polar bear, or “Nanuuq,” as
the Eskimos call it, lives only in the
Northern Hemisphere, on the arctic
ice cap, and spends most of its time in
coastal areas. Polar bears are widely
dispersed in Canada, extending from
the northern arctic islands south to the
Hudson Bay area. They are also found
in Greenland, on islands off the coast
of Norway, on the northern coast of
the former Soviet Union, and on the
northern and northwestern coasts of
Alaska in the United States.
Some polar bears may make extensive
north-south migrations as the pack ice
recedes northward in the spring and
advances southward in the fall. They
also may travel long distances during
the breeding season to find mates, or in
up/USGS
search of food.
Appearance
Steve Amstr
The polar bear is the largest member
Female polar bears prepare small dens on the mainland or on sea ice where they will
of the bear family, with the exception
give birth and spend winter. Usually two cubs are born in December or January. While
of Alaska’s Kodiak brown bears, which
the cubs are born blind, hairless, and no bigger than squirrels, they grow very rapidly.
equal polar bears in size. Males stand
Polar bear cubs remain with their mother for 2-1/4 years.
from 8 to 11 feet tall and generally
weigh from 500 to 1,000 pounds, but may These adaptations help the polar bear
important food sources for polar bears.
weigh as much as 1,400 pounds. Females from slipping on ice.
In fact, because of their acute sense of
usually stand 8 feet tall and weigh 400 to
smell, polar bears can sense carcasses
700 pounds, but may reach 700 pounds.
Feeding Habits
from many miles away.
Part of the reason the polar bear weighs Because the polar bear rarely eats
so much is that it stores about a 4-inch
vegetation, it is considered a carnivore,
Polar bears can cover significant
layer of fat to keep it warm. The polar
or meat-eater. The ringed seal is the
distances on land, but are most agile in
bear has a longer, narrower head and
polar bear’s primary prey. A polar bear
the sea. They are excellent swimmers,
nose, and smaller ears, than other bears. may stalk a seal by waiting quietly
and can reach speeds of up to 6 mph in
for it to emerge from its blow hole or
the water. They are good divers, too.
Although the polar bear’s coat appears
“atluk,” an opening seals make in the ice When being pursued by hunters in open
white, each individual hair is actually
allowing them to breathe or climb out
water, polar bears have been known to
a clear, hollow tube. Some of the sun’s
of the water to rest. The polar bear will
escape by plunging 10 to 15 feet below
rays bounce off the fur, making the
often have to wait for hours for a seal to
the surface and resurfacing a good
polar bear’s coat appear white. During
emerge. Because the polar bear’s coat
distance away. They also have been seen
the summer months, adult bears molt,
is camouflaged against the whiteness of
swimming 100 miles or more from ice or
or gradually shed their coats and grow
the ice and snow, the seal may not see
land.
new ones, which look pure white. By
the bear. Polar bears typically eat only
the following spring, the sunshine has
the seal’s skin and blubber, or fat, and
Reproduction
caused their coats to turn a yellowish
the remaining meat is an important food Polar bears reach breeding maturity at
shade. Polar bears sometimes have a
source for other animals of the Arctic.
3 to 5 years of age. Males may travel
yellowish shade to their coats due to
For example, Arctic foxes feed almost
great distances in search of female
staining from seal oils.
entirely on the remains of polar bear
mates. While breeding usually takes
kills during the winter.
place in April and May, the embryos
The polar bear’s coat helps it blend in
may not implant (develop) until the
with its snow-covered environment,
Polar bears also prey on walrus, but,
following year, depending on whether
which is a useful hunting adaptation.
because of the walrus’s ferocity and
the mother has had a stable enough
The polar bear’s front legs appear
size, bears are usually only successful
supply of food to sustain herself while
slightly bow-legged and pigeon-toed,
preying on the young. The carcasses
allowing her to feed the developing cubs
and fur covers the bottoms of its paws.
January 1998
of whales, seals, and walrus are also
through the winter.

---

In October and November, pregnant
females seek sites on the mainland or
on sea ice to dig small dens in snow
where they will give birth and spend the
winter. The temperature inside the polar
bear’s den can be as much as 40 degrees
warmer than outside. Usually two cubs
are born in December or January. When
the cubs first arrive, they are blind,
hairless, and no bigger than squirrels.
However, the cubs grow rapidly from
their mother’s rich milk.
As soon as spring comes, the mother
bear leads her cubs to the coast along
the open sea, where seals and walrus
are abundant. The mother will fiercely
protect her cubs from any perceived
danger. The cubs remain with their
mother for 2-1/4 years. Because of this,
most adult female polar bears breed
only every third year.
Special Adaptations
The blubber and fat of ringed seals
provides polar bears with the nutrients
Susanne Miller/USFWS
they need to stay warm in their harsh
environment. They can eat other
importation of polar bears or their parts important habitats, harvest allocations
sources of food, but their bodies demand and products into the United States.
based on sustainability, collection of
the high caloric intake from ringed
Eskimos and other Alaska Natives are
biological information, and increased
seals. Terrestrial sources cannot meet
allowed to harvest some polar bears for
consultation and cooperation with state,
the high caloric needs of polar bears,
subsistence and handicraft purposes.
local, and private interests. The Fish
and consequently terrestrial foods
The Fish and Wildlife Service is the
and Wildlife Service also undertakes
cannot substitute for the loss of access
federal agency responsible for managing education and outreach efforts to inform
to seals. Polar bears store energy in the
polar bears under the Marine Mammal
the public about how polar bears can be
form of fat, most of which they acquire
Protection Act.
protected from over-harvest.
from consuming these seals.
An international conservation
A number of protective measures have
The most productive seal-hunting
agreement for polar bears signed in
been taken to reduce human activities
periods are during the spring and early
1976 by the United States, the former
along the coast in polar bear denning
summer (before the ice retreats) and
Soviet Union, Norway, Canada, and
areas. This is when the animals are most
following the open-water period in the
Denmark (Greenland) also provides for
sensitive to outside disturbances. For
fall. Because changes in sea ice are most cooperative management of polar bears. example, oil and gas pipelines and roads
dramatic during the summer/fall, this
have been routed to avoid these areas.
is the time when it can be hardest for
The Fish and Wildlife Service and the
The Fish and Wildlife Service also
bears to hunt seals. A reduction in sea
U.S. Geological Survey’s Alaska Science provides expertise to industries on how
ice can extend the time period during
Center work together to monitor polar
to minimize conflicts with bears while
which bears do not have access to their
bears in Alaska, where they number
conducting their operations.
primary prey. The effects of a longer ice-
approximately 3,500, and study their
free season can cause a decline in polar
behavior. Cooperative efforts with
Today, it is estimated that there
bear health, reproduction, survival,
Canada involve monitoring polar bears
are 20,000 to 25,000 polar bears
and population size. Polar bear survival
in the Beaufort Sea, and the agencies
worldwide. With continued cooperative
depends on large and accessible seal
work with the Russian government to
management, these great marine
populations and vast areas of ice from
monitor the animals in the Chukchi Sea.
mammals, and the unique arctic
which to hunt.
environment on which they depend, can
Another treaty, the “Agreement between be protected for generations to come.
Protection
the Government of the United States
Polar bears have traditionally played
of America and the Government of the
an important role in the culture and
Russian Federation on the Conservation
livelihood of Eskimos and other Native
and Management of the Alaska-
people of the North. They depend on the Chukotka Polar Bear Population,”
animals for food and clothing.
unifies the American and Russian
management programs that affect this
U. S. Fish and Wildlife Service
In the United States, polar bears are
shared population of bears. Notably, the
Endangered Species Program
a federally protected species under
treaty calls for the active involvement
4401 N. Fairfax Drive, Room 420
the Marine Mammal Protection Act of
of Native people and their organizations Arlington, VA 22203
1972. This protection prohibits hunting
in future management programs. It
703-358-2171
of polar bears by non-Natives and
also enhances long-term joint efforts
http://www.fws.gov/endangered/
establishes special conditions for the
such as conservation of ecosystems and
May 2008

---