Grizzly Bear

Grizzly Bear

Overview
The grizzly bear also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...

 (Ursus arctos) that generally lives in the uplands of western North America. This subspecies is thought to descend from Ussuri brown bear
Ussuri Brown Bear
The Ussuri brown bear , also known as the black grizzly is a subspecies of the brown bear found in the Ussuri krai, Sakhalin, the Amur Oblast, northward to the Shantar Islands, Iturup Island, northeastern China, the Korean peninsula, Hokkaidō and Kunashiri Island. This subspecies is thought to be...

s which crossed to Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 from eastern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 100,000 years ago, though they did not move south until 13,000 years ago.

Grizzlies are normally solitary, active animals, but in coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...

al areas, the grizzly congregates alongside stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...

s, lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

s, river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

s, and ponds during the salmon spawn
Salmon run
The salmon run is the time at which salmon swim back up the rivers in which they were born to spawn. All Pacific salmon die after spawning. While most Atlantic salmon die after their first spawn, about 5-10% return to the sea to feed between spawnings. The annual run is a major event for sport...

.
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Encyclopedia
The grizzly bear also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...

 (Ursus arctos) that generally lives in the uplands of western North America. This subspecies is thought to descend from Ussuri brown bear
Ussuri Brown Bear
The Ussuri brown bear , also known as the black grizzly is a subspecies of the brown bear found in the Ussuri krai, Sakhalin, the Amur Oblast, northward to the Shantar Islands, Iturup Island, northeastern China, the Korean peninsula, Hokkaidō and Kunashiri Island. This subspecies is thought to be...

s which crossed to Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 from eastern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 100,000 years ago, though they did not move south until 13,000 years ago.

Grizzlies are normally solitary, active animals, but in coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...

al areas, the grizzly congregates alongside stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...

s, lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

s, river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

s, and ponds during the salmon spawn
Salmon run
The salmon run is the time at which salmon swim back up the rivers in which they were born to spawn. All Pacific salmon die after spawning. While most Atlantic salmon die after their first spawn, about 5-10% return to the sea to feed between spawnings. The annual run is a major event for sport...

. Every other year, females (sows) produce one to four young (commonly two) which are small and weigh only about 500 grams (1.1 lb). A sow is protective of her offspring and will attack if she thinks she or her cubs are threatened.

Name


The word "grizzly" in its name refers to "grizzled" or grey hairs in its fur
Fur
Fur is a synonym for hair, used more in reference to non-human animals, usually mammals; particularly those with extensives body hair coverage. The term is sometimes used to refer to the body hair of an animal as a complete coat, also known as the "pelage". Fur is also used to refer to animal...

, but when naturalist George Ord
George Ord
George Ord was an American ornithologist.Ord was born in Philadelphia, Pennsylvania. His father was a rope maker and Ord joined him in the business, continuing after his father's death in 1806...

 formally named the bear in 1815, he misunderstood the word as "grisly", to produce its biological Latin specific or subspecific name "horribilis".

Description


Most adult female grizzlies weigh 130–200 kg (286.6–440.9 lb), while adult males weigh on average 180–360 kg (396.8–793.7 lb). The average total length in this subspecies is 198 centimetres (6.5 ft), with an average shoulder height of 102 centimetres (3.3 ft) and hindfoot length of 28 centimetres (11 in). Newborn bears may weigh less than 500 grams (1.1 lb). In the Yukon River
Yukon River
The Yukon River is a major watercourse of northwestern North America. The source of the river is located in British Columbia, Canada. The next portion lies in, and gives its name to Yukon Territory. The lower half of the river lies in the U.S. state of Alaska. The river is long and empties into...

 area, mature female grizzlies can weigh as little as 100 kilograms (220.5 lb). On the other hand, an occasional huge male grizzly has been recorded which greatly exceeds ordinary size, with weights reported up to 680 kilograms (1,499.1 lb). Although variable from blond to nearly black, grizzly bear fur is typically brown in color with white tips. A pronounced hump appears on their shoulders; the hump is a good way to distinguish a black bear from a grizzly bear, as black bears do not have this hump.

Range


Brown bears are found in Asia, Europe and North America giving them one of the widest ranges of bear species. The ancestors of the grizzly bear originated in Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

 and travelled to North America approximately 50,000 years ago. This is a very recent event in evolutionary time, causing the North American grizzly bear to be very similar to the brown bears inhabiting Europe and Asia.

In North America, grizzly bears previously ranged from Alaska to Mexico and as far east as the Hudson Bay
Hudson Bay
Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

 area. In North America, the species is now found only in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, south through much of western Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, and into portions of the northwestern United States
Northwestern United States
The Northwestern United States comprise the northwestern states up to the western Great Plains regions of the United States, and consistently include the states of Oregon, Washington, Idaho, Montana, Wyoming, to which part of southeast Alaska is also sometimes included...

 including Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

, Washington and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, extending as far south as Yellowstone
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

 and Grand Teton National Park
Grand Teton National Park
Grand Teton National Park is a United States National Park located in northwestern Wyoming, U.S. The Park consists of approximately and includes the major peaks of the long Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Only south of Yellowstone...

s, but is most commonly found in Canada.

In September 2007, a hunter produced evidence of grizzly bears returning to the Selway-Bitterroot Wilderness
Selway-Bitterroot Wilderness
The Selway-Bitterroot Wilderness is a protected wilderness area in the states of Idaho and Montana, in the northwestern United States.At 1.3 million acres , it is one of the largest designated wilderness areas in the United States . It spans the Bitterroot Mountain Range, on the border between...

 ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

, in Idaho and western Montana, by killing a male grizzly bear.

Its original range also included much of the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...

 and the southwestern states, but it has been extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...

 in most of those areas.

The grizzly bear appears on the flag of California
Flag of California
The Bear Flag is the official flag of the state of California. The precursor of the flag was first flown during the 1846 Bear Flag Revolt and was also known as the Bear Flag.-Design:...

, though they are extinct in the state
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...

, the last one having been shot in 1922.

In Canada, there are approximately 25,000 grizzly bears occupying British Columbia, Alberta, the Yukon, the Northwest Territories, Nunavut
Nunavut
Nunavut is the largest and newest federal territory of Canada; it was separated officially from the Northwest Territories on April 1, 1999, via the Nunavut Act and the Nunavut Land Claims Agreement Act, though the actual boundaries had been established in 1993...

 and the northern part of Manitoba. Combining Canada and the United States, grizzly bears inhabit approximately half the area of their historical range. In British Columbia, grizzly bears inhabit approximately 90% of their original territory. There were approximately 25,000 grizzly bears in British Columbia when the European settlers arrived. However, population size significantly decreased due to hunting and habitat loss. In 2008, it was estimated there were 16,014 grizzly bears. Population estimates for British Columbia are based on hair-snagging, DNA-based inventories, mark-recapture and a refined multiple regression model.

Other provinces and the United States may use a combination of methods for population estimates. Therefore, it is difficult to say precisely what methods were used to produce total population estimates for Canada and North America, as they were likely developed from a variety of studies. The grizzly bear currently has legal protection in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, European countries, some areas of Canada and in the United States. However, it is expected that repopulating its former range will be a slow process, due to a variety of reasons including the reintroduction of competing predators to these areas, the effects of reintroducing such a large animal to areas prized for agriculture and livestock, and due to the bear's slow reproductive habits. There are currently about 55,000 wild grizzly bears located throughout North America.

Brown bears (of which the grizzly bear is a subspecies) can live up to 30 years in the wild, though 20 to 25 is normal.

Reproduction



Grizzly bears have one of the lowest reproductive rates of all terrestrial mammals in North America. This is due to numerous ecological factors. Grizzly bears do not reach sexual maturity until they are at least five years old. Once mated with a male in the summer, the female delays embryo implantation until hibernation, during which miscarriage can occur if the female does not receive the proper nutrients and caloric intake. On average, females produce two cubs in a litter and the mother cares for the cubs for up to two years, during which the mother will not mate. Once the young leave or are killed, females may not produce another litter for three or more years, depending on environmental conditions. Male grizzly bears have large territories, up to 4000 square kilometres (1,544.4 sq mi), making finding a female scent difficult in such low population densities.

Grizzlies are subject to population fragmentation
Population fragmentation
Population fragmentation is a form of population segregation. It is often caused by habitat fragmentation. Population fragmentation causes inbreeding depression, which leads to a decrease in genetic variability in the species involved. This decreases the fitness of the population for several reasons...

, which tends to reduce the population by causing inbreeding depression
Inbreeding depression
Inbreeding depression is the reduced fitness in a given population as a result of breeding of related individuals. It is often the result of a population bottleneck...

.

Diet



Although grizzlies are of the order Carnivora
Carnivora
The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...

 and have the digestive system of carnivores, they are normally omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...

s, since their diet consists of both plants and animals. They have been known to prey on large mammals, when available, such as moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...

, deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

, sheep, elk
Elk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...

, bison
American Bison
The American bison , also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds...

, caribou,and even black bears
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...

. Grizzly bears feed on fish such as salmon, trout, and bass, and those with access to a more protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

-enriched diet in coastal areas potentially grow larger than interior individuals. Grizzly bears also readily scavenge food on carrion left behind by other animals.

Canadian or Alaskan grizzlies are larger than those that reside in the American Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

. This is due, in part, to the richness of their diet. In Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the grizzly bear's diet consists mostly of whitebark
Whitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...

 pine nut
Pine nut
Pine nuts are the edible seeds of pines . About 20 species of pine produce seeds large enough to be worth harvesting; in other pines the seeds are also edible, but are too small to be of great value as a human food....

s, tuber
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...

s, grasses, various rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, army cutworm
Army cutworm
The army cutworm is a species of moth .Its caterpillars are pests of oat and common wheat .-Location:...

 moths and scavenged carcasses. None of these, however, match the fat content of the salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

 available in Alaska and British Columbia.

Although the diet of grizzly bears varies extensively based on seasonal and regional changes, plants make up a large portion of their diet, with some estimates as high as 80-90%. Various berries constitute an important food source when they are available. These can include blueberries (Vaccinium cyanococcus), blackberries (Rubus fruticosus), salmon berries (Rubus spectabilis), cranberries (Vaccinium oxycoccus), buffalo berries (Shepherdia argentea
Shepherdia argentea
Shepherdia argentea is a species of Shepherdia, native to central North America from southern Canada south in the United States to northern California and New Mexico.It is a deciduous shrub growing to 2–6 m tall...

), and huckleberries (Vaccinium parvifolium
Vaccinium parvifolium
Red Huckleberry is a species of Vaccinium native to the western North America, where it is common in forests from southeastern Alaska and British Columbia south through western Washington and Oregon to central California. In the Oregon Coast Range, it is the most common Vaccinium...

), depending on the environment. Insects such as ladybugs, ants and bees are eaten if they are available in large quantities. In Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

, it has been observed that grizzly bears may obtain half of their yearly caloric needs by feeding on Miller moths that congregate on mountain slopes. When food is abundant, grizzly bears will feed in groups. For example, many grizzly bears will visit meadows right after there has been an avalanche or glacier slide. This is due to an influx of legumes, such as Hedysarum
Hedysarum
Hedysarum is a genus of the botanical family Fabaceae, consisting of about 309 species of annual or perennial herbs in Asia, Europe, North Africa, and North America.-Description:...

, which the grizzlies consume in massive amounts. When food sources become scarcer, however, they separate once again.

In preparation for winter, bears can gain approximately 400 lb (181.4 kg), during a period of hyperphagia, before going into false hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...

. The bear often waits for a substantial snowstorm before it enters its den: such behaviour lessens the chances that predators will find the den. The dens are typically at elevations above 1800 metres (5,905.5 ft) on north-facing slopes. There is some debate amongst professionals as to whether grizzly bears technically hibernate: much of this debate revolves around body temperature and the ability of the bears to move around during hibernation on occasion. Grizzly bears can "partially" recycle their body wastes during this period. In some areas where food is plentiful year round, grizzly bears skip hibernation altogether.

Interspecific competition



Most notable in Yellowstone have been the interactions between gray wolves
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...

 and grizzly bears. With the reintroduction of gray wolves to Yellowstone, many visitors have witnessed a once common struggle between a keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...

, 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 in the defense of young or over a carcass, which is commonly an elk
Elk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...

 killed by wolves. The grizzly bear uses its keen sense of smell to locate the kill. 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 quick nips at its hind legs. Thus, the bear will sit down and use 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 is not usually worth the risk to the wolves (if the bear has the upper hand due to strength and size) or to the bear (if the wolves are too numerous or persistent).

Black bears generally stay out of grizzly territory, but grizzlies may occasionally enter black bear terrain to obtain food sources both bears enjoy, such as pine nuts, acorns, mushrooms, and berries. When a black bear sees a grizzly coming, it either turns tail and runs or climbs a tree. Black bears are not strong competition for prey because they have a more herbivorous diet. Confrontations are rare because of the difference in size, habitat, and diet of the bear species. When this happens, it is usually with the grizzly being the aggressor. The black bear will only fight when it is a smaller grizzly such as a yearling or when the black bear has no other choice but to defend itself.

The segregation of black bear and grizzly bear populations is possibly due to competitive exclusion. In certain areas, grizzly bears outcompete black bears for the same resources. For example, many Pacific coastal islands off of British Columbia and Alaska support either the black bear or the grizzly, but rarely both. In regions where both species coexist, they are divided by landscape gradients such as age of forest, elevation and openness of land. Grizzly bears tend to favor old forests with high productivity, higher elevations and more open habitats compared with black bears.

The relationship between grizzly bears and other predators is mostly one-sided; grizzly bears will approach feeding predators to steal their kill. In general, the other species will leave the carcasses for the bear to avoid competition or predation. Any parts of the carcass left uneaten are scavenged by smaller animals.
Cougars
Cougars
Cougars is a Chicago-based rock band signed to the New York-based label Go-Kart Records.The Cougars' music is often compared to that of Rocket from the Crypt...

, however, generally give the bears a wide berth. Grizzlies have less competition with cougars than with other predators, such as coyotes, wolves, and other bears. When a grizzly descends on a cougar feeding on its kill, the cougar usually gives way to the bear. When a cougar does stand its ground, the cougar will use its superior agility and its claws to harass the bear, yet stay out of its reach until one of them gives up.

Coyotes, foxes, and wolverines are generally regarded as pests to the grizzlies rather than competition, though they may compete for smaller prey, such as ground squirrels and rabbits. All three will try to scavenge whatever they can from the bears. Wolverines are aggressive enough to occasionally persist until the bear finishes eating, leaving more than normal scraps for the smaller animal.

Ecological role


The grizzly bear has several relationships with its ecosystem. One such relationship is a mutualistic relationship with fleshy-fruit bearing plants. After the grizzly consumes the fruit, the seeds are dispersed and excreted in a germinable condition. Some studies have shown germination success is indeed increased as a result of seeds being deposited along with nutrients in feces. This makes grizzly bears important seed distributors in their habitats.

While foraging for tree roots, plant bulbs, or ground squirrels, bears stir up the soil. This process not only helps grizzlies access their food, but also increases species richness in alpine ecosystems. An area that contains both bear digs and undisturbed land has greater plant diversity than an area that contains just undisturbed land. Along with increasing species richness, soil disturbance causes nitrogen to be dug up from lower soil layers, and makes nitrogen more readily available in the environment. An area that has been dug by the grizzly bear has significantly more nitrogen than an undisturbed area.

Nitrogen cycling is not only facilitated by grizzlies digging for food, it is also accomplished via their habit of carrying salmon carcasses into surrounding forests. It has been found that spruce tree (Picea glauca) foliage within 500 m (1,640.4 ft) of the stream where the salmon have been obtained contains nitrogen originating from salmon on which the bears preyed. These nitrogen influxes to the forest are directly related to the presence of grizzly bears and salmon.

Grizzlies directly regulate prey populations and also help prevent overgrazing in forests by controlling the populations of other species in the food chain. An experiment in Grand Teton National Park
Grand Teton National Park
Grand Teton National Park is a United States National Park located in northwestern Wyoming, U.S. The Park consists of approximately and includes the major peaks of the long Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Only south of Yellowstone...

 in Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 showed removal of wolves and grizzly bears caused populations of their herbivorous prey to increase. This, in turn, changed the structure and density of plants in the area, which decreased the population sizes of migratory birds. This provides evidence grizzly bears represent a keystone predator, having a major influence on the entire ecosystem they inhabit.

Conflicts with humans


Grizzlies are considered by some experts to be the most aggressive bears even by the standards of brown bears. Aggressive behavior in grizzly bears is favored by numerous selection variables. Unlike the smaller black bears, adult grizzlies are too large to escape danger by climbing trees, so they respond to danger by standing their ground and warding off their attackers. Increased aggressiveness also assists female grizzlies in better ensuring the survival of their young to reproductive age. Mothers defending cubs are the most prone to attacking, being responsible for 70% of fatal injuries to humans. Historically, bears have competed with other large predators for food, which also favors increased aggression.


Grizzly bears normally avoid contact with people. In spite of their obvious physical advantages and many opportunities, they almost never view humans as prey; bears rarely actively hunt humans. Most grizzly bear attacks result from a bear that has been surprised at very close range, especially if it has a supply of food to protect, or female grizzlies protecting their offspring. In such situations, property may be damaged and the bear may physically harm the person.

Exacerbating this is the fact that intensive human use of grizzly habitat coincides with the seasonal movement of grizzly bears. An example of this spatiotemporal intersection occurs during the fall season: grizzly bears congregate near streams to feed on salmon when anglers
Angling
Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...

 are also intensively using the river. Some grizzly bears appear to have learned to home in on the sound of hunters' gunshots in late fall as a source of potential food, and inattentive hunters have been attacked by bears trying to appropriate their kills.

Increased human-bear interaction has created "problem bears", which are bears that have become adapted to human activities or habitat. Aversive conditioning, a method involving using deterrents such as rubber bullets, foul-tasting chemicals or acoustic devices to teach bears to associate humans with negative experiences, is ineffectual when bears have already learned to positively associate humans with food. Such bears are translocated or killed because they pose a threat to humans. The B.C. government kills approximately 50 problem bears each year and overall spends more than one million dollars annually to address bear complaints, relocate bears and kill them.

For back-country campers
Camping
Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...

, hanging food between trees at a height unreachable to bears is a common procedure, although some grizzlies can climb and reach hanging food in other ways. An alternative to hanging food is to use a bear canister.

Traveling in groups of six or more can significantly reduce the chance of bear-related injuries while hiking
Hiking
Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...

 in bear country.

Protection


The grizzly bear is listed as threatened in the contiguous United States and endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 in parts of Canada. In May 2002, the Canadian Species at Risk Act listed the Prairie population (Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

, Saskatchewan
Saskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....

 and Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...

 range) of grizzly bears as being wiped out in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. As of 2002, grizzly bears were listed as Special Concern under the COSEWIC registry and considered threatened under the U.S. Fish and Wildlife Service.

Within the United States, the U.S. Fish and Wildlife Service concentrates its effort to restore grizzly bears in six recovery areas. These are Northern Continental Divide (Montana), Yellowstone (Montana, Wyoming, and Idaho), Cabinet-Yaak (Montana and Idaho), Selway-Bitterroot (Montana and Idaho), Selkirk (Idaho and Washington), and North Cascades (Washington). The grizzly population in these areas is estimated at 750 in the Northern Continental Divide, 550 in Yellowstone, 40 in the Yaak portion of the Cabinet-Yaak, and 15 in the Cabinet portion (in northwestern Montana), 105 in Selkirk region of Idaho, 10–20 in the North Cascades, and none currently in Selway-Bitterroots, although there have been sightings. These are estimates because bears move in and out of these areas, and it is therefore impossible to conduct a precise count. In the recovery areas that adjoin Canada, bears also move back and forth across the international boundary.

The U.S. Fish and Wildlife Service claims the Cabinet-Yaak and Selkirk areas are linked through British Columbia, a claim that is disputed.

All national parks, such as Banff National Park
Banff National Park
Banff National Park is Canada's oldest national park, established in 1885 in the Rocky Mountains. The park, located 110–180 kilometres west of Calgary in the province of Alberta, encompasses of mountainous terrain, with numerous glaciers and ice fields, dense coniferous forest, and alpine...

, Yellowstone
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

 and Grand Teton
Grand Teton National Park
Grand Teton National Park is a United States National Park located in northwestern Wyoming, U.S. The Park consists of approximately and includes the major peaks of the long Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Only south of Yellowstone...

, and Theodore Roosevelt National Park
Theodore Roosevelt National Park
Theodore Roosevelt National Park is a United States National Park comprising three geographically separated areas of badlands in western North Dakota. The park was named for U.S. President Theodore Roosevelt, in honor of his achievements in conservation as president and for the landscape's...

 have laws and regulations in place to protect the bears. Even so, grizzlies are not always safe in parks. In Glacier National Park in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

 and Banff National Park
Banff National Park
Banff National Park is Canada's oldest national park, established in 1885 in the Rocky Mountains. The park, located 110–180 kilometres west of Calgary in the province of Alberta, encompasses of mountainous terrain, with numerous glaciers and ice fields, dense coniferous forest, and alpine...

 in Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

, grizzlies are regularly killed by trains as the bears scavenge for grain that has leaked from poorly maintained grain cars. Road kills on park roads are another problem. The primary limiting factors for grizzly bears in Alberta and elsewhere are human-caused mortality, unmitigated road access, and habitat loss, alienation, and fragmentation. In the Central Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 Ecosystem, most bears have died within a few hundred meters of roads and trails.

On 9 January 2006, the US Fish and Wildlife Service proposed to remove Yellowstone grizzlies from the list of threatened and protected species. In March 2007, the U.S. Fish and Wildlife Service "de-listed" the population, effectively removing Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...

 protections for grizzlies in the Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

 area. Several environmental organizations, including the NRDC, brought a lawsuit against the federal government to relist the grizzly bear. On September 22, 2009, U.S. District Judge Donald W. Molloy
Donald W. Molloy
Donald W. Molloy is a senior United States federal judge on the United States District Court for the District of Montana.Born in Butte, Montana, Molloy received a B.A. from the University of Montana in 1968 and a J.D. from the University of Montana School of Law in 1976. He was in the United...

 reinstated protection due to the decline of whitebark pine
Whitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...

 tree, whose nuts are a main source of food for the bears. In 1996 the International Union for Conservation of Nature moved the grizzly bear to "Lower Risk Least Concern" status on the IUCN Red List.

Farther north, in Alberta, Canada, intense DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 hair-snagging studies on 2000 showed the grizzly population to be increasing faster than what it was formerly believed to be, and Alberta Sustainable Resource Development calculated a population of 841 bears. In 2002, the Endangered Species Conservation Committee recommended that the Alberta grizzly bear population be designated as threatened due to recent estimates of grizzly bear mortality rates that indicated the population was in decline. A recovery plan released by the Provincial government in March 2008 indicated the grizzly population is lower than previously believed. The Provincial government has so far resisted efforts to designate its declining population of about 700 grizzlies (previously estimated at as high as 842) as endangered.

Environment Canada consider the grizzly bear to a "special concern" species, as it is particularly sensitive to human activities and natural threats. In Alberta and British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, the species is considered to be at risk. In 2008, it was estimated there were 16,014 grizzly bears in the British Columbia population, which was lower than previously estimated due to refinements in the population model.

The Mexican grizzly bear (Ursus arctos nelsoni) is extinct.

Conservation efforts



Conservation efforts have become an increasingly vital investment over recent decades, as population numbers have dramatically declined. Establishment of parks and protected areas are one of the main focuses currently being tackled to help reestablish the low grizzly bear population in British Columbia. One example of these efforts is the Khutzeymateen Grizzly Sanctuary located along the north coast of British Columbia; at 44300 hectares (109,467.6 acre) in size, it is composed of key habitat for this threatened species. Regulations such as limited public access, as well as a strict no hunting policy, have enabled this location to be a safe haven for local grizzlies in the area. When choosing the location of a park focused on grizzly bear conservation, factors such as habitat quality and connectivity to other habitat patches are considered.

The Refuge for Endangered Wildlife located on Grouse Mountain in Vancouver is an example of a different type of conservation effort for the diminishing grizzly bear population. The refuge is a five-acre terrain which has functioned as a home for two orphaned grizzly bears since 2001. The purpose of this refuge is to provide awareness and education to the public about grizzly bears, as well as providing an area for research and observation of this secluded species.

Another factor currently being taken into consideration when designing conservation plans for future generations are anthropogenic barriers in the form of urban development and roads. These elements are acting as obstacles, causing fragmentation of the remaining grizzly bear population habitat and prevention of gene flow between subpopulations (for example, Banff National Park). This, in turn, is creating a decline in genetic diversity, and therefore the overall fitness of the general population is lowered. In light of these issues, conservation plans often include migration corridors by way of long strips of "park forest" to connect less developed areas, or by way of tunnels and overpasses over busy roads. Using GPS collar tracking, scientists can study whether or not these efforts are actually making a positive contribution towards resolving the problem. To date, most corridors are found to be infrequently used, and thus genetic isolation is currently occurring, which can result in inbreeding and therefore an increased frequency of deleterious genes through genetic drift. Current data suggest female grizzly bears are disproportionately less likely than males to use these corridors, which can prevent mate access and decrease the number of offspring.

Hunting


Trophy hunting causes an imbalance between the male and female sexes, since older males are primarily sought to be hunted for their size. The hunting of older males creates a gender imbalance within an area specific population. The killing of older male bears in their own territory allows other males to migrate in and claim the late bear's territory. Older male bears will have had cubs with existing female bears in the region. This may cause the newly migrated male bear to become potentially infanticidal towards cubs of the resident females and the late male bear.

See also

  • Brown bear
    Brown Bear
    The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...

  • Grizzly-polar bear hybrid
    Grizzly-polar bear hybrid
    A grizzly–polar bear hybrid is a rare ursid hybrid that has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid in nature was confirmed by testing the DNA for a strange-looking bear that had been shot near Sachs Harbour, Northwest Territories on Banks Island in the...

  • Grizzly Peak (Berkeley Hills)
    Grizzly Peak (Berkeley Hills)
    Grizzly Peak is a summit in the Berkeley Hills above Berkeley, California. The peak is located on the border between Alameda and Contra Costa counties, within the boundaries of Tilden Regional Park, and directly behind the University of California, Berkeley campus.The peak was named for the...

  • List of fatal bear attacks in North America
  • Hunting Status On Grizzly Bears in British Columbia, Canada
    Hunting Status On Grizzly Bears in British Columbia, Canada
    Grizzly bear hunting has become a hotly debated issue in British Columbia. On one side are government bodies like the BC Ministry of Environment, various First Nations and the BC Wildlife Federation arguing for the continued sustainable harvest of grizzly bears...


External links