Polar Bear Photos (Ursus
maritimus)
The polar bear photographs on this were taken in both Alaska and Canada. All images may be licensed as stock photos for business use, or purchased as display pictures for home or office decor.
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Polar bear on sea ice in the Beaufort Sea, Arctic Ocean, off the coast of Alaska. © Patrick J. Endres Of all mammals, the Polar bear captures the imagination as
the great lord of the Northern Hemisphere. It's solitary existence
in remote and severe locations provoke mystery and intrigue.
As the top trophic level carnivore in the remote arctic, they
have uniquely adapted to this harsh and unforgiving environment.
General description
Polar bears have uniquely adapted to life in the Arctic environment. However, their population has been shriking and scientists attribute the decrease to a warming climate and therefore habitat alterations in the Arctic. © Patrick J. Endres Adaptations by the polar bear to life on sea ice include:
- a white coat with water repellent guard hairs and dense
under fur,
- short furred snout,
- short ears,
- teeth specialized for a carnivorous rather than an omnivorous
diet,
- and hair nearly completely covering the bottom of the
feet.
Twin cubs are common among polar bears. © Patrick J. Endres Cubs weigh between 1 and 2 pounds (0.5-0.9 kg) at birth.
An extremely large adult male may weigh 1,500 pounds (680
kg). Most mature males weigh between 600 and 1,200 pounds
(273-545 kg), and are between 8 and 10 feet (2.4-3.0 m) in
length. Mature females weigh 400 to 700 pounds (182-318 kg).
Life history
Polar bears live a solitary existence most of the year. © Patrick J. Endres
- Bears are polygamous, and the male remains with a receptive
female a relatively short time and then seeks another female.
- Pregnant females seek out denning areas in late October
and November. Denning occurs on land and on sea ice.
- A denning female excavates a depression in the snow under
a bank, on a slope, or near rough ice. She enlarges the
denning chamber as drifting snow accumulates in depth.
- Young are born in the den in December.
- A litter of two is the most common.
- The female cubs emerge from the den in late March or early
April when cubs weigh about 15 pounds (6.8 kg).
- They make short trips to and from the open den for several
days as the cubs become acclimated to outside temperatures.
They then start traveling on the drifting sea ice.
- Young most commonly remain with the mother until they
are about 28 months old.
- Females can breed again at about the same time they separate
from their young, so normally they can produce litters every
third year.
- Bears in the wild have been recorded as old as 32 years
but most probably do not live beyond 25 years.
Distribution and migration
Polar bears are well insulated from the
cold by nearly 4 inches of blubber.© Patrick J. Endres
- In winter, bears off Alaska commonly occur as far south
as St. Lawrence Island and may even reach St. Matthew Island
and the Kuskokwim Delta.
- During the summer, bears occur near the edge of the pack
ice in the Chukchi Sea and Arctic Ocean, mostly between
70° and 72° north latitude.
- Pregnant females concentrate for winter denning on Wrangel
Island and other Russian islands, islands in the Canadian
arctic, Greenland, and Spitsbergen.
- Some denning occurs along the north Alaska coast, especially
within the Arctic National Wildlife Refuge and on the adjacent
sea ice.
- Mark and recapture studies indicate that there are several
populations of polar bears in the polar basin that have
relatively little interchange with one another. Off Alaska
there are two populations.
- The Beaufort Sea population occurs along the North Slope
of Alaska and ranges into western Canada.
- The Chukchi population occurs off western Alaska with
its range extending to Wrangel Island and eastern Siberia.
Foods
Polar bears play in Churchill, Manitoba, CANADA © Patrick J. Endres Bears prey to a lesser extent on:
- bearded seals,
- walruses, and beluga whales.
- They also feed on carrion, including whale, walrus, and
seal carcasses they find along the coast.
- They occasionally eat small mammals, bird eggs, and vegetation
when other food is not available.
- A keen sense of smell, extremely sharp claws, patience,
strength, speed, and the camouflaging white coat aid in
procuring food.
Human uses
Polar bear coexist with Alaska native villages. © Patrick J. Endres Polar bears occur in areas under the jurisdiction of five
nations--Russia, Norway, Denmark, Canada, and the United States--and
also on the high seas where jurisdiction is not clearly defined.
In Alaska prior to the late 1940s, nearly all polar bear hunting
was by Eskimos with dog teams. Sport hunting, sometimes with
the use of aircraft, started in the late 1940s and continued
through 1972. In 1972 the state of Alaska prohibited the use
of aircraft in polar bear hunting. With the passage of the
Statehood Act, Alaska began a polar bear management program.
State regulations required sealing of skins, provided a preference
for subsistence hunters, and protected cubs and females with
cubs.
The federal Marine Mammal Protection
Act (MMPA)
Degradation to polar bear habitat is currently of more concern than effects of hunting on populations. Human activities, especially those associated with oil and gas exploration and extraction, pose the greatest immediate threat. © Patrick J. Endres Representatives of the five polar bear nations prepared an
international agreement on conservation of polar bears in
November 1973. The pact was ratified in 1976. It allows bears
to be taken only in areas where they have been taken by traditional
means in the past and prohibits the use of aircraft and large
motorized vessels as an aid to taking. The agreement has created
a high seas polar bear sanctuary but does not prohibit recreational
hunting from the ground using traditional methods. In Canada,
recreational hunting of polar bears currently provides significant
economic benefits to Native people.
The stocks of polar bears in Alaska are shared with other
nations and national management programs should be coordinated.
In 1988, the North Slope Borough Department of Wildlife Management
(representing Alaska Natives) and the Inuvialuit Game Council
(representing Canadians) signed an agreement to provide for
coordinated management of the Beaufort Sea polar bear stock.
Negotiations are currently underway between the U.S. and Russia
for an agreement on management for the Chukchi stock.
Degradation to polar bear habitat is currently of more concern
than effects of hunting on populations. Human activities,
especially those associated with oil and gas exploration and
extraction, pose the greatest immediate threat. Oil exploration
and drilling activities in denning areas could cause bears
to den in less suitable areas. Oil spills from offshore drilling
and transportation of oil through ice covered waters could
contaminate bears and reduce the insulating value of their
fur, or adversely affect animals in the food chain below them.
Severe environmental conditions would hinder or prevent containment
of a spill, and currents and ice movement could distribute
oil over large areas
Text by Jack Lentfer
Revised by Lloyd Lowry and reprinted 1994
taken
from Fish & Game Wildlife Notebook Series
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As superb swimmers, the Polar bear's long
neck helps them track in water.
Twins are common but triplets and even four
cubs are possible, however, more than two rarely survive.
Polar bears eye sight is at least as good
as a humans, but the rely primarily on their sense of smell, able
to sniff out a seal from 25 miles away.
Cubs stay with their mother for two to three
years, learning how to hunt and survive in the Arctic.
Polar bears are sexually dimorphic, with
the males considerably larger than the females.
 The
United States Marine Mammal Protection Act of 1972 included a
moratorium on hunting marine mammals by people other than Alaska
Natives.
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| (907) 479-9196
| Patrick J. Endres | P.O. Box 81312 | Fairbanks, Alaska 99708
| Unauthorized reproduction prohibited by copyright law.