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| Serious looking Grizzly in Yellowstone National Park. |
The
grizzly bear has the reputation of being the most ferocious
and dangerous
animal in North America.
Grizzlies vary widely
in body shape, color and in the shape of their heads.
The tundra grizzly is often creamy yellow on the back
with brownish
legs and underparts. In the Rocky Mountains, the “silver-tip” phase
is dominant. Adults weigh from 136 to 526 kg and are
prodigiously strong.
Although grizzlies
try to avoid contact with humans, when enco
untered
they are unpredictable and should
be given plenty of room. They move with a slow shambling walk,
the low-slung head swinging from side to side.
They can move very quickly, however, and even horses
find
it difficult to
evade a rushing grizzly.
The grizzly
once inhabited almost all of western North
America but, with the arrival of the Europeans
in the 1500's their numbers were reduced until now they
are restricted chiefly to the Canadian Rockies and
Alaska with a small, healthy and growing population in
the Yellowstone Region
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| Grizzly catching a morning snooze |
Grizzlys
occupy a variety of habitats, from the desert's
edge to the high mountain forests, tundra,
and alpine meadows. grizzlys
were common on the Great Plains prior
to the arrival of European
settlers.
Grizzly bears mature sexually between
4-6 years of age, but continue growing
until
10-11 years old.
Bears have
been known to live and reproduce in the
Greater Yellowstone area at 25 years of
age and have
a potential lifespan of 50 years.The number
of offspring
avg is 2 cubs. They stay with the mama sow
for 2+ years.
Young grizzilys are born blind and furless,
weighing only 340 to 680 grams.
By 3 months
old cubs weigh about32 pounds, by 6 months
weight averages 60 pounds.
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| Grizzly shaking off a swim across Indian Creek in Yellowstone National Park. |
Brown bears in the wild can live for 20 to 30 years,
although most brown bears die in their first few
years of life. In captivity, brown bears have been
known to
live up to 50 years.
The grizzly may be active at any time
of the day, but generally forage for food in
the morning and evening
and sleep durning the day. Seasonal movements
of the grizzily have been observed, with bears
sometimes traveling dozens of miles
during the fall to reach areas of favorable
food supplies, such
as white pine nuts and abundant berry
patches.
Home ranges overlap extensively and
there is no evidence of territorial defense, although
bears
are generally
solitary. Occasionally, bears may gather in
large numbers at major food sources and form family foraging
groups
with more than one age class of young.
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Three two year old grizzly bear
cubs scratch on pole in Grand Teton
National
Park |
Grizzilys begin hibernation
in October to December, and they come out of their den in
March to
May, with the exact period dependent on the
location,
weather, and condition
of the individual. Most often, brown
bears dig their own dens and make a bed out
of dry vegetation. Burrows are usually located
on a sheltered slope, either
under a large stone or among the roots of a
mature tree. Dens are sometimes used repeatedly
year after year.
Grizzlys move with a slow,
lumbering walk, although they are capable of moving very
quickly and
can reach 35 miles per hour on short bursts. grizzly
bears have an excellent sense of smell and are able to follow
the scent of a rotting
carcass for
more than
two miles.
Brown bears are omnivorous, eating
almost anything nutritious. Their diet changes with seasonal
availability of different
food sources. They eat a wide variety of plant foods,
including grasses, sedges,
roots, moss, and bulbs.
Fruits, nuts, berries, bulbs, and tubers are taken extensively
during summer and early autumn. They consume insects,
fungi, and roots at all times of the year and also
dig
mice, ground squirrels, marmots, and other fossorial
animals out of their burrows. Moth larvae have been
demonstrated to be especially important sources of protein
and fat
when brown bears are putting on fat in the fall.
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Galloping Grizzly Bear, Yellowston National Park |
Rocky Mountain grizzly bears
are quite carnivorous, hunting moose, elk, mountain
sheep, and
mountain goats. Occasionally black bears
are preyed upon.
Because of their size and aggressiveness
towards threats, brown bears are not often preyed upon.
Humans have persecuted
them throughout recent history and some cubs may
be attacked by other bears, mountain lions
or wolves, although
this is very rare.
Grizzly bears have been long
considered the most dangerous animal in North America, although
real
danger
of attack
from this animal is often exagerated. In general,
brown bears attempt to avoid human contact and will
not attack
unless startled at close quarters with young or
engrossed in a search for food.
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Two year
old grizzly bear cub hams it up for camera. |
Economic Importance for
Humans: Positive
Grizzly bears have been widely sought
as big game trophies and are currently subject to regulated
sport hunting
throughout much of their range. Grizzly bears
help the ecotourism industry, especially in areas
such as Yellowstone
National Park,
Wyoming and parts of Alaska.
Ways that people
benefit from these animals.
Grizzly bear
numbers have dropped dramatically since
the turn of the century, when settlers and livestock
flooded the West, driving these bears out of much
of their former range. Grizzlies now cling to a mere
2 per
cent of their former rnge. Logging, mining, road
construction, resorts, subdivisions, golf courses,
etc. have all encroached
on suitable bear habitat, resulting in a decrease
in bear numbers. Grizzly numbers were estimated at
100,000 in the conterminous United States in the early 1900's,
but there are now fewer than 1,000. Brown bears
are still
fairly common in the mountainous regions of western
Canada and Alaska, perhaps numbering about 30,000 individuals.
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