Polar bears are among the largest predators in the world. They range in color
from pure white after a molt to a yellowish shade resulting from solar oxidation
or staining by oil from seal blubber. Their skin, nose and lips are black in
color. Polar bears’ long neck and narrow skull aid in streamlining the
animal in water, and their large, flat and oar-like front feet make them strong
swimmers. Their fur is thicker than any other bears’ even covering their feet,
for warmth and traction on ice. Polar bears also have a thick layer of blubber
which provides buoyancy and insulation.
Height 8 to 10 feet
Weight Adult males 550-1700 lbs; females 200 - 700
Lifespan 20 - 25 years
Staples Almost exclusively feed on ringed seals and to a lesser extent
Also eat walrus, beluga whale and bowhead whale carcasses,
birds, vegetation and kelp
The World Conservation Union (IUCN) estimates that there are
between 20,000-25,000 polar bears in the world.
Polar bears are distributed throughout the arctic region in 19
subpopulations. Alaska, Canada, Russia, Greenland and Norway have polar bear
Highly dependant on older stable pack ice in the arctic region, polar bears
spend much of their time on the ice hunting, mating and denning. They are
generally solitary as adults, except during breeding and cub rearing.
Unlike brown bears, non breeding females and males do not hibernate or den in
the winter. Pregnant polar bears need to eat a lot in the summer and fall in
order to build up sufficient fat reserves for surviving the denning period,
during which time they give birth to one-pound cubs and then nurse them to about
20-30 pounds before emerging from the den in March or April.
Mating Season Late March through May
Gestation About 8
months with delayed implantation
Litter size 1-4 cubs; 2 cubs most
Female bears locate denning sites in October on thick stable
pack ice or on land. The young are born from November through January while the
mothers are hibernating. Cubs will remain with their mothers for at least 2 ½
years. Female polar bears can produce five litters in their lifetime, which is
one of the lowest reproductive rates of any mammal.
Climate change, which is causing the loss of older
stable sea ice and the thinning, disappearance and moving offshore
of older sea ice, is reducing essential polar bear habitats and is the
great threat to their survival. Loss of sea ice leads to higher energy
requirements to locate prey and a shortage of food. This causes higher
mortality among cubs and reduction in size among first year cubs and
adult males. For example, in Alaska 42% of cubs now reach 12 months of
age, down from 65% 15 years ago. Another threat is human-caused
mortality. Some bears are attracted by unsecured garbage and animal
carcasses. This can eventually lead to conflicts between people and
bears and lethal removal of the bear. Illegal killing (poaching) of
bears also remains another factor causing their decline.
The polar bear was listed as
threatened under the federal Endangered Species Act* on May 14,
2008. This move officially recognizes that polar bears are
threatened with extinction from global warming, which is melting the Arctic sea
ice where polar bears hunt for ringed and bearded seals, their primary food
In May 2006, the International Union for the
Conservation of Nature added the polar bear to its "Red List"
of the world’s most imperiled animals, predicting a 30% reduction in the polar bear population in the
next 45 years.
*The Endangered Species Act requires the US federal government to
identify species threatened with extinction, identify habitat they need to
survive, and help protect both. In doing so, the Act works to ensure the
basic health of our natural ecosystems and protect the legacy of conservation we
leave to our children and grandchildren.
The polar bear is the youngest and largest of the world’s bear
species, only matched in mass by the largest of Alaska’s Kodiak
grizzlies. It’s also the only completely carnivorous bear, feeding
primarily on ringed seals rather than leaves, berries, or bark, and it
may be the most hardy mammal in its ability to survive long periods
deprived of food and water. Yet this mighty hunter and fierce defender
of its young is also among the world’s most vulnerable animals — the
polar bear’s might is no match for the greenhouse gas-fueled global
warming that’s rapidly melting its sea-ice habitat.
ENDANGERED SPECIES ACT PROFILE
May 14, 2008 - Defenders of Wildlife welcomes decision to list
polar bears as threatened under the Endangered Species Act, points out
Bush administration still unwilling to address global warming.
Read the Press Release
PROTECTION STATUS: Threatened
YEAR PLACED ON LIST: 2008
CRITICAL HABITAT: None
RECOVERY PLAN: None
RANGE: In and around the Arctic Ocean with southernmost occurrence at
Canada’s James Bay; populations occur within jurisdictions of the
United States ( Alaska), Canada, Denmark (Greenland), Norway, and Russia
THREATS: Primarily melting of sea-ice habitat due to intensifying
global warming, in combination with other threats including oil and gas
development, environmental contaminants such as PCBs, industrial noise
and harassment from increased Arctic shipping and other activities, and
overhunting in some areas
Polar bear numbers increased following the establishment of hunting
regulations in the 1970s and today stand at 20,000 to 25,000. The rapid
decline of Arctic sea-ice due to global warming has reversed this
trend, and currently at least five of the 19 polar bear populations
including those in Western Hudson Bay are declining. Scientists
estimate that if the Arctic continues its melting trend, the worldwide
polar bear population will decline by two-thirds by 2050 and will be
near extinction by the end of the century. As actual sea-ice melting
has proceeded much faster than predicted by scientific models,
population declines may occur much faster as well.