|
The
grizzly bear, once found over most of western North America, now is restricted
mainly to western Canada and Alaska. It is listed as threatened in the
lower 48 states, where it survives only in parts of the northern Rockies
and northern Cascades. Conflict with humans and loss of habitat led to
its present status. The last grizzly bear was killed in the Black Hills
in 1894.
Yellowstone,
with about 200 grizzlies in the Greater Yellowstone Area, Glacier,
with 200, and North Cascades National Park, with an unknown number
of bears, are protected sanctuaries for a large part of the population
remaining in the lower 48 states. Intensive research on grizzly
bears in Yellowstone and Glacier national parks has led to the current
management practices. Unnatural food sources such as garbage dumps
have been closed and visitors and employees are educated to store
food away from bears. Steps are taken to reduce the likelihood of
bear-human encounters in the backcountry. A guideline coordinates
grizzly bear management in all the northwestern states. Interagency
cooperation is a key element in all three park areas, but especially
in the Greater Yellowstone region, which includes the national park,
several national forests, and other adjacent lands. North Cascades
National Park in Washington is gathering data on its grizzlies and
their habitat so protective measures can be taken.
The grizzly
bear is the undisputed "king" amongst all North American
animals. It spends most of its waking hours foraging for food in
dense forests, tundra, and lower alpine regions associated with
mountain ranges in Western Canada, Alaska, Wyoming, Montana, Idaho
and Washington. The grizzly is also found in small pockets in Russia,
Europe and Asia.
The grizzly
is the second largest terrestrial carnivore in North America, next
to the polar bear. The grizzly bear is synonymous with mountain
ranges whereas the polar bear frequents flat tundra and ice packs
in the north. The grizzly is more accurately described as an omnivore,
not a carnivore. It consumes a variety of plants and the occasional
meat from carrion or prey.
Adult boars
or male grizzlies can weigh in at 1100 pounds (500 kilograms), but
average between 550 and 780 pounds (250 and 350 kilograms). Grizzly
sows or females weigh about half as much as their male counterparts.
Grizzlies have heavy stout bodies with powerful legs. They have
relatively large heads with a dish-like profile and a characteristic
muscle hump over the shoulders. The tips of the guard hairs on a
grizzly can turn white or gray, giving it a "grizzled"
appearance. Grizzlies have much longer claws than black bears. They
are strong diggers with an appetite for plant roots or burrowing
animals. Grizzlies are powerful, can run 35 mph (60 kph), have excellent
eyesight and a legendary keen sense of smell. These traits make
it a formidable animal at the top of the food chain.
The female grizzly or sow attains sexual maturity at 2 to 3 years
of age. A pregnant sow usually gives birth to 2 or 3 cubs (up to
a maximum of 4) in the month of January or February and begins to
nurse them in the den. A newborn cub weighs 1.25 to 1.5 pounds (600
to 700 gms) and is blind, hairless and toothless. By the time the
sow and its cubs are ready to emerge from the den in April, the
cubs weigh in at 18 pounds (8 kilograms). The sow stays with her
cubs for a period of 2½ to 3 years and will defend them against
any thread, including a much bigger and stronger boar. During this
period of time she teaches them how to survive in the wild. After
this "personal development" session is completed, she
chases the cubs away so they can fend for themselves.
Before the onset
of winter, grizzlies forage for food around the clock to gain enough
weight to survive their winter sleep. Unlike smaller hibernating
animals that lower their core temperature considerably, grizzlies
drop their body temperature by a mere 5 degrees Celsius. As a result,
they can easily be aroused from sleep. After they have prepared
their dens for the winter, they often remain outside the den for
3 weeks or so without feeding. They plod along until their bodies
tell them to shut down for the long hard winter.
|
|