The
grizzly bear, sometimes called the
silvertip bear, is a
powerful brownish-yellow bear that lives in the uplands of western North
America. It has traditionally been treated as a subspecies,
Ursus arctos
horribilis, of the brown bear living in North America.
Grizzly bears reach weights of 180–680 kilograms (400–1,500 pounds); the male
is on average 1.8 times as heavy as the female, an example of sexual dimorphism.
This dimorphism suggests that size is an important factor in male/female
competition. Their colouring ranges widely across geographic areas, from blond to
deep brown or black. These differences, once attributed to sub speciation, are
now thought to be primarily due to the different environments these bears
inhabit, particularly with regard to diet and temperature.
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The grizzly has a large hump over the shoulders which is a muscle mass used
to power the forelimbs in digging. The head is large and round with a concave
facial profile. In spite of their massive size, these bears can run at speeds of
up to fifty-five kilometres per hour (thirty-five miles per hour).
Normally a solitary nocturnally active animal, in coastal areas the grizzly
congregates alongside streams and rivers during the salmon spawn. Every other
year females (sows) produce one to four young (most commonly two) which
are small and weigh only about 500 grams (one pound). Sows are very protective
of their offspring.
Range
The current range of the grizzly bear extends from Alaska, south through much
of western Canada, and into portions of the northwestern United States including
Idaho, Montana, Washington and Wyoming, extending as far south as Yellowstone
and Grand Teton National Parks, but is most commonly found in Canada. There may
still be a small population in Colorado in the southern San Juan Mountains. In
September 2007 a hunter produced evidence of grizzly rehabilitation in the
Selway-Bitterroot ecosystem by killing a male grizzly.[10]
Its original range also included much of the Great Plains and the southwestern
states, but it has been extirpated in most of those areas.
The grizzly currently
enjoys legal protection in the United States, Canada, Mexico, and European
countries. However, it is expected that its re-population of its former range
will be a slow process, due equally to the ramifications of reintroducing such a
large animal to areas which are prized for agriculture and livestock and also to
the bear's slow reproductive habits (bears invest a good deal of time in raising
young). There are currently about 60,000 wild grizzly bears located throughout
North America. These bears weigh from 100 to 1200 pounds.
Brown bears (of which the grizzly bear is a subspecies) can live up to thirty
years in the wild, though twenty to twenty-five is normal.[11]
Name
The word "grizzly" in its name refers to "grizzled" or grey hairs in its fur,
but when naturalist George Ord formally named the bear in 1815 he misunderstood
the word as "grisly", to produce its biological Latin specific or sub
specific
name "horribilis".[9]
Diet
Bears have been known to prey on large mammals such as moose, deer, sheep,
caribou and even black bears. Grizzly bears will feed on fish such as salmon,
trout, and bass, and those with access to a more protein-enriched diet in
coastal areas potentially grow larger than interior individuals. Grizzly bears
will readily scavenge food, behaviour that can lead them into conflict with other
species, such as wolves and humans.
The grizzly bears that reside in the American northwest are not as large as
Canadian or Alaskan sub-species Ursus arctos. This is due, in part, to
the richness of their diet which in Yellowstone consists of white bark pine nuts,
roots, tubers, grasses, various rodents, army cutworm moths and scavenged
carcasses, none of which match the fat content of the salmon available in
Alaska. During early spring, as the bears emerge from their dens, elk and bison
calves are actively sought. The bear will move in a zigzag pattern, nose to the
ground, hoping to find a meal.
In preparation for winter, bears will gain hundreds of kilograms of fat,
during a period of hyperphagia, before going into a state of false hibernation.
The bear will often wait for a substantial snowstorm before it enters its den.
Presumably, this behaviour lessens the chances that predators will be able to
locate the den. The dens themselves are typically located at elevations above
6,000 feet on northern-facing slopes. There is some debate amongst professionals
as to whether grizzly bears technically hibernate. Much of the debate revolves
around body temperature and the ability of the bears to move around during
hibernation on occasion. Grizzly bears have the ability to "partially" recycle
their body wastes during this period. In some areas where food is plentiful year
round, grizzly bears forgo hibernation altogether.
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| Grizzly Bear sow and cub in Shoshone National Forest |
Interspecies competition
Most notable in Yellowstone have been the interactions between gray wolves
and grizzly bears. Since the reintroduction of gray wolves to Yellowstone, many
lucky visitors have witnessed a once common struggle between a keystone species,
the grizzly bear, and its historic rival, the gray wolf. The interactions of
U. arctos horribilis with the wolves of Yellowstone have been under
considerable study. Typically, the conflict will be over a carcass, which is
commonly an elk killed by wolves. The grizzly bear will use its strong sense of
smell to locate the kill first. Then the wolves and grizzly will play a game of
cat and mouse. One wolf may try to distract the bear while the others feed. The
bear then may retaliate by chasing the wolves. If the wolves become aggressive
with the bear it is normally in the form of careful nips at its hind legs. Thus,
the bear will sit down and ease its ability to protect itself in a full circle.
Rarely do interactions such as these end in death or serious injury to either
animal. One carcass simply isn't usually worth the risk to the wolves if the
bear has the upper hand (due to strength and size) or the bear (if the wolves
are too numerous or persistent). Over time, it seems the grizzly bears have
benefited from the presence of the gray wolf because of increased food
availability.
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| Grizzly cub at Knight Inlet, British Columbia, Canada |
Safety
camping in grizzly territory
During the continuous evolution of the grizzly bear a premium has been placed
on spatial memory. Without this adaptation, the species would not be able to
forage efficiently over large territories. This strong sense of memory thus ties
in with their tendency to return to human habitations which rewarded them with
food in the past.
It is imperative for all campers in bear country (both black and grizzly) to
maintain a "clean" site. Reports have indicated that something as innocuous as a
tube of chap stick has enticed a bear to come near a campsite in search of food.
Any bear conditioned to finding food around campsites will almost always return
and expect the same reward. The bear is then a threat to campers and itself,
since park rangers will be forced to kill it.
For backcountry campers, hanging food between trees at a height unreachable
to bears is a common procedure.
Safety
hiking in grizzly territory
Hiking in grizzly territory requires a different set of rules than hiking in
your local park. The consequences of making a mistake can be deadly and are well
documented.
First, it is imperative that you are aware of your surroundings at all times.
Recognizing grizzly sign is the first defence in preventing an attack. A grizzly
track is unlike that of a black bear in that one can trace a single line from
the innermost (closest to the foot pad) point on the left toe to the innermost
point on the right toe without intersecting the pad of the foot.
Other signs include: talus slopes that appear raked, fallen logs which have
been torn up, and high claw marks on trees.
Surprising a bear typically precedes the most violent attacks. By making
noise, at a cost to the ambient peacefulness of nature, you can assure yourself
that a bear will know you are there. They are usually calm but may occasionally
attack if disturbed. This technique works in the case of a lone grizzly
wandering through the area, or the more dangerous high strung sow with cubs of
the year. It will not work when a bear has a carcass near the trail. In this
situation, the hiker must listen for ravens or other scavengers which may too be
hanging around the kill site.
If the bear does not exit the premises as you approach, it's time to make a
series of potentially life saving decisions. First, back away and talk to the
bear in a calm voice. If it hasn't charged, it probably doesn't consider you a
threat. Keep backing away (DO NOT RUN) and try in any way to make yourself seem
less threatening.
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| Two grizzly bears in a meadow |
In the unfortunate event that the bear does charge, and you are not equipped
with bear spray, promptly drop to the ground stomach first, leaving your
backpack on as a barrier between the bear and you, and cover your head and ears
with your arms (hands interlocking behind your head). Drawing your legs up
tightly under you will also decrease the chances of a bite in a soft vulnerable
arterial area, and of being dragged by that appendage. In this situation
fighting back will almost certainly intensify and prolong the attack.
Legal
status
The grizzly bear is listed as threatened in the contiguous United States, and
endangered in parts of Canada. In May 2002, the Canadian Species at Risk Act
listed the Prairie population (Alberta, Saskatchewan and Manitoba range) of
grizzly bears as being extirpated in Canada. In Alaska and parts of Canada
however, the grizzly is still legally shot for sport by hunters. On January 9,
2006, the US Fish and Wildlife service proposed to remove Yellowstone grizzlies
from the list of threatened and protected species.
Some biologists have argued that the word horribilis should be removed
from the bear's taxonomic name, as its negative connotations may hinder
conservation efforts. This change would not be permitted by the International
Code of Zoological Nomenclature.
Protection
Many national parks, such as Yellowstone and Grand Teton, have laws and
regulations in place to protect the bears. Also the grizzly bears are very
protective of their young and are willing to go to any level to protect them.
On March 22, 2007, The Federal Government stated that Grizzly bears in and
around Yellowstone National Park no longer need Endangered Species Act
protection.
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| Grizzly Bears in a play fight. |
Trivia
The grizzly bear became the state animal of California in 1953 and appears
on the state flag. The last grizzly bear in California was shot in August 1922
in Tulare County, eleven years after the state legislature had adopted the
flag[2].
Grizzlies are not tree-climbers since their long front claws are not adapted
for climbing.[1] They, however, can
have a long reach (10 ft. or more), and some can climb for short distances.[2]
