Biologists estimate their
population at 22,000 to 27,000 bears, of which around 15,000 are in Canada.
Mammalia (Mammals) Order: Carnivora Family: Ursidae Genus:Ursus Species: maritimus Shoulder height: up to 5.3 feet (1.6 meters) Length: 6.6 to 10 feet (2 to 3 meters) Weight: males—660 to 1,760 pounds (300 to 800 kilograms);
females—330 to 660 pounds (150 to 300 kilograms) Life span: 25 to 30 years in the wild, up to 45 years in zoos Gestation: 6.5 months Number of young at birth: 1 to 4, with two being the average Size at birth: 1.3 pounds (.6 kilograms) Age of maturity: males—10 to 11 years; females—5 to 6 years
scientific order Carnivora includes bears, dogs, cats, raccoons, otters,
weasels, and their relatives. All typical carnivores have well developed
claws and a pair of specialized cheek teeth for cutting hard foods.
Family - Ursidae- All
bears belong to this family. The family is divided into three subfamilies,
Ursinae (black bears, brown bears, polar bears, sloth bears, and sun bears),
Tremarctinae (spectacled bears), and Ailuropodinae (giant pandas).
Genus, species - Ursus
There are five other
species in the genus Ursus: brown bears, American black bears, Asiatic
black bears, sun bears, and sloth bears. Species can be distinguished by
size, build, coloration, and habitat.
. Ursus maritimus is Latin
for "sea bear".
United Nations Environment Programme (UNEP)
bears spend much of their time at or near the edge of the pack ice. This is
where they are most likely to find food. As the southern edge of the arctic
ice cap melts in summer, some bears will follow the retreating ice north to
stay close to seals and other prey. Other bears spend their summers on land,
living off body fat stored from successful hunting in the spring and winter.
When the ice returns in the fall, the bears leave land to resume life on the
sea ice.The world's southern-most polar bears live year-round in James Bay,
Canada. The species range extends as far south as the winter maximum sea ice
extent and includes adjacent land masses
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 search of food.
polar bear rides a summer sea-ice raft off Norway's Svalbard archipelago. Sea
ice provides crucial habitat for the Arctic's top predator, but warming
temperatures are creating extended ice-free periods that tax bears. www.visionsofthewild.com
The polar bear is the largest
member of the bear family, with the exception of Alaska’s Kodiak brown bears,
which equal polar bears in size. Males stand from 8 to 11 feet tall and
generally weigh from 500 to 1,000 pounds, but may weigh as much as 1,400 pounds.
Females usually stand 8 feet tall and weigh 400 to 700 pounds, but may reach 700
pounds. Part of the reason the polar bear weighs so much is that it stores about
a 4-inch layer of fat to keep it warm.
The polar bear has a longer,
narrower head and nose, and smaller ears, than other bears.
Although the polar bear’s coat
appears white, each individual hair is actually a clear, hollow tube. Some of
the sun’s rays bounce off the fur, making the polar bear’s coat appear
white. During the summer months, adult bears molt, or gradually shed their coats
and grow new ones, which look pure white. By the following spring, the sunshine
has caused their coats to turn a yellowish shade. Polar bears also sometimes may
have a yellowish shade to their coats caused by staining from seal oils.
Polar bears live on ice and snow,
but that’s not a problem—these bears have some cool ways to stay warm!
Hair— A dense, thick
undercoat of fur is protected by an outer coat of long guard hairs that
stick together when wet, forming a waterproof barrier to keep them dry. Even
though polar bears look white, their hair is really made of clear, hollow
tubes filled with air.
Blubber— Blubber helps
insulate polar bears from the freezing air and cold water, and acts as a
nutritional reserve when food can’t be found. This blubber also helps the
bears float in the water. It is 2 to 4 inches (5 to 10 centimeters) thick.
Winter Sleep— When the
temperature outside drops, many bears stay warm by making a den and
sleeping. Polar bears do not hibernate, but their body functions do slow
down at this time. Many scientists call this “winter sleep,” because the
bears can easily be awakened. A mother polar bear can give birth and nurse
her young while still in her winter sleep.
Florian Schulz watched a Svalbard male (background) stalk a female with
two cubs, alert to danger
The polar bear’s coat helps it
blend in with its snow-covered environment, which is a useful hunting
adaptation. The polar bear’s front legs appear slightly bowllegged and
pigeon-toed, and fur covers the bottoms of its paws. These adaptations help the
polar bear keep them from slipping on ice.
Polar bears are mainly meat
eaters, and their favorite food is seal. They will also eat walrus, caribou,
beached whales, grass, and seaweed. Polar bears are patient hunters, staying
motionless for hours above a seal's breathing hole in the ice, just waiting for
a seal to pop up.
Because the polar bear rarely
eats vegetation, it is considered a carnivore, or meat-eater. The ringed seal is
the polar bear’s primary prey. A polar bear may stalk a seal by waiting
quietly for it to emerge from its blow hole or “atluk,” an opening seals
make in the ice allowing them to breathe or climb out of the water to rest. The
polar bear will often have to wait for hours for a seal to emerge. Because the
polar bear’s coat is camouflaged against the whiteness of the ice and snow,
the seal may not see the bear. Polar bears typically eat only the seal’s skin
and blubber, or fat, and the remaining meat is an important food source for
other animals of the Arctic. For example, Arctic foxes feed almost entirely on
the remains of polar bear kills during the winter. Polar bears also prey on
walrus, but, because of the walrus’s ferocity and size, bears are usually only
successful preying on the young. The carcasses of whales, seals, and walrus are
also important food sources for polar bears. In fact, because of their acute
sense of smell, polar bears can sense carcasses from many miles away.
Polar bears can cover significant
distances on land, but are most agile in the sea. They are excellent swimmers,
and can reach speeds of up to 6 mph in the water. They are good divers, too.
When being pursued by hunters in open water, polar bears have been known to
escape by plunging 10 to 15 feet below the surface and resurfacing a good
distance away. They also have been seen swimming 100 miles or more from ice or
Steve Hillebrand / USFWS
Polar bears reach breeding
maturity at 3 to 5 years of age. Males may travel great distances in search of
female mates. While breeding usually takes place in April, the embryos may not
implant (develop) until the following year, depending on whether the mother has
had a stable enough supply of food to sustain herself while allowing her to feed
the developing cubs through the winter.
In October and November, male
polar bears begin to head out on the pack ice where they spend the winter.
Pregnant females, however, seek sites on the mainland or on sea ice to dig large
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 the rich milk provided by their mother.
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.
Polar bears have traditionally
played an important role in the culture and livelihood of Eskimos and other
Native people of the North. They depend on the animals for food and clothing. In
the United States, polar bears are a federally protected species under the
Marine Mammal Protection Act of 1972. This protection prohibits hunting of polar
bears by non-Natives and establishes special conditions for the importation
of polar bears or their parts and products into the United States. Eskimos
and other Alaska Natives are allowed to harvest some polar bears for subsistence
and handicraft purposes. The U.S. Fish and Wildlife Service is the federal
agency responsible for managing polar bears under the Marine Mammal Protection
Circle (Oct. 2003) -- Three Polar bears approach the starboard bow of the Los
Angeles-class fast attack submarine USS Honolulu (SSN 718) while surfaced 280
miles from the North Pole. Sighted by a lookout from the bridge (sail) of the
submarine, the bears investigated the boat for almost 2 hours before leaving.
Commanded by Cmdr. Charles Harris, USS Honolulu while conducting otherwise
classified operations in the Arctic, collected scientific data and water samples
for U.S. and Canadian Universities as part of an agreement with the Artic
Submarine Laboratory (ASL) and the National Science Foundation (NSF). USS
Honolulu is the 24th Los Angeles-class submarine, and the first original design
in her class to visit the North Pole region. Honolulu is as assigned to
Commander Submarine Pacific, Submarine Squadron Three, Pearl Harbor, Hawaii. U.
S. Navy photo by Chief Yeoman Alphonso Braggs.
young Polar bear stands up to get a better look at the Los Angeles-class fast
attack submarine USS Honolulu (SSN 718) while surfaced 280 miles from the North
Pole.U. S. Navy photo by Chief Yeoman Alphonso Braggs
seen through the periscope of the Los Angeles-class fast attack submarine USS
Honolulu (SSN 718), a young Polar bear investigates the open water around the
submarine’s rudder U. S.
Navy photo by Chief Yeoman Alphonso Braggs
An international conservation
agreement for polar bears signed in 1976 by the United States, the former Soviet
Union, Norway, Canada, and Denmark (Greenland) also provides for cooperative
management of polar bears. The Fish and Wildlife Service and the United States
Geological Survey’s Alaska Science Center work together to monitor polar bears
in Alaska, where they number approximately 4,700, and study their behavior.
Cooperative efforts with Canada involve monitoring polar bears in the Beaufort
Sea, and the agencies work with the Russian government to monitor the animals in
the Chukchi Sea.
bear with cub. Credit: Scott Schliebe/USFWS
Another treaty, the “Agreement
between the Government of the United States of America and the Government of the
Russian Federation on the Conservation and Management of the Alaska-Chukotka
Polar Bear Population,” unifies the American and Russian management programs
that affect this shared population of bears. Notably, the treaty calls for the
active involvement of Native people and their organizations in future management
programs. It will also enhance long-term joint efforts such as conservation of
ecosystems and important habitats, harvest allocations based on sustainability,
collection of biological information, and increased consultation and cooperation
with state, local, and private interests. The Fish and Wildlife Service also
undertakes education and outreach efforts to inform the public about how polar
bears can be protected from over-harvest.
Bear at Cape Churchill (Wapusk National Park, Manitoba, Canada) photo taken by
Polar Bears at Risk
The area covered by arctic sea
ice is melting at an unprecedented rate. Polar bears need sea ice to access
their food, and to move from hunting grounds to their denning or summer
Toxic chemicals transported to
the Arctic from the south have long-term effects on polar bear health and
Oil exploration in
the Arctic affects polar bears by fragmenting and disturbing their habitat,
and by introducing oil and other toxic substances to their environment.
Although much of the
traditional harvesting in local communities is sustainable, the main threat
to polar bears in some areas is still over-hunting.
| Arctic Bears | A Changing World | PBS
In Alaska, demands for oil,
natural gas, and other resources have led to some conflicts between polar bears
and humans. A number of protective measures have been taken to reduce human
activities along the coast in polar bear denning areas. This is when the animals
are most sensitive to outside disturbances. For example, oil and gas pipelines
and roads have been routed to avoid these areas. The Fish and Wildlife Service
also provides expertise to industries on how to minimize conflicts with bears
while conducting their operations. Today it is estimated that there are 20,000
to 25,000 polar bears worldwide. With continued cooperative management, these
great marine mammals, and the unique arctic environment on which they depend,
can be protected for generations to come.
Polar bears range throughout the
Arctic in areas where they can hunt seals at open leads. The five "polar
bear nations" where the ice bears are found include the U. S. (Alaska),
Canada, Russia, Denmark (Greenland), and Norway.
the North Pole (Apr. 27, 2003) -- During Exercise ICEX 2003, the Seawolf-class
attack submarine USS Connecticut (SSN 22) surfaced and broke through the ice.
This polar bear, attracted by the hole which can be used to find food, was seen
through the sub's periscope and these photos were captured as the image was
projected on a flat-panel display. After investigating the Connecticut for
approximately 40 minutes, the bear left the area, with no damage to the sub or
to the bear. U.S. Navy photo by Mark Barnoff
Biologists estimate their
population at 22,000 to 27,000 bears, of which around 15,000 are in Canada. In
1973, the five nations with polar bear populations (Canada, Denmark, which
governed Greenland, Norway, the U.S., and the former U.S.S.R.) entered into the
International Agreement for the Conservation of Polar Bears. Here is what they
encounter in each nation:
In Norway, polar bears are
completely protected and have been since 1973. On the glacial Svalbard
islands, their population has rebounded from a low of about 1,000 to roughly
2,000 bears. Scientists are worried, however, about the effects of pollution
on the bears. PCB levels in the polar bears of Norway and western Russia are
two-and-a-half to seventeen times higher than those in North American
In Canada, Hudson Bay's ice
melts about three weeks earlier each spring than it did just 25 years ago,
which has greatly shortened the time that the bears can hunt for food.
(Polar bears need a platform of ice from which to hunt seals.) Canadian
scientists have observed that today's polar bears are smaller in stature,
weigh less, and have fewer cubs. The bears in certain areas of Canada have
excessive levels of PCBs and other contaminants. In Canada, native hunting
is allowed under the provision of the International Agreement. Each
community is given a quota, and natives are permitted to sell their right to
hunt a bear to non-natives. Roughly 500 bears are harvested each year
In Alaska, about 100 polar
bears are harvested every year by natives under the subsistence provision of
the Marine Mammal Protection Act. The only restriction in place is that if
they kill a bear, the carcass must be used in some way. Natives are not
allowed to sell the skins, but may make and sell products from them.
In Greenland, which is
governed by Denmark, natives may hunt polar bears but are forbidden from
selling any bear parts. Roughly 100 bears are harvested each year.
Russia's polar bears face an
uncertain future. Russian natives were recently granted the right to hunt,
which worries Russian scientists because the breakdown of law and order and
the collapse of the Russian economy has led to widespread poaching problems.
They worry that legal hunting will encourage further poaching. In addition,
polar bears in western Russia are exposed to dangerously high levels of
polar bear cub curiously stands on its hind legs while its mother stays
nearby. The two bears approached within 200 meters of the ship.
Scientists analyzing decades
of data from Arctic Sea ice recently reported a significant reduction in the
thickness of the ice during the last decade. The scientists found a decrease
in sea ice all across the Arctic Ocean. Polar bears need sea ice so they can
hunt for seals. A retreat and loss of sea ice could make it harder for these
animals to get enough food. Pregnant females and those with cubs may be
particularly at risk.
Climate changes on
prey species will have a negative effect on polar bears
can result reduced success in successfully entering seal birth lairs
or increased seasonal rain patterns could effect seal pupping by not
providing adequate snow for construction of birth lairs or if rain fall
by collapsing birth lairs thus reducing seal productivity
reductions could effect polar bear condition and ultimately cub
production and survival
Changes that alter
the period of ice coverage could affect distribution and impact polar bears
spend greater amounts of time on land
of terrestrial areas would ultimately effect physical condition of bears
when forced to rely on fat stores
physical condition could effect production and survival
deteriorating pack ice may experience increased energetic costs
associated with movements and swimming
Denning could be
impacted by unusual warm spells
access to high
quality denning areas may be limited or restricted
use of less
desirable denning habitat could have impacts on reproduction and
warming could directly cause snow dens could collapse or be opened to
thermal insulative properties in opened dens could effect litter
find out more about Polar Bears visit the sites below by clicking on the
Credit: U.S. Fish & Wildlife
Service, San Diego Zoo, Sea World, NOAA, International Bear Association, United
compiled from The British Antarctic Study, NASA, Environment Canada,
UNEP, EPA and other sources as stated and credited Researched by Charles
Welch-Updated daily This Website is a project of the The Ozone Hole Inc.
a 501(c)(3) Nonprofit Organization http://www.theozonehole.com