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 |
