Grizzly Bear Animal
The grizzly bear (Ursus arctos horribilis), also known as the North American brown bear or simply grizzly, is a population or subspecies[2] of the brown bear inhabiting North America.
grizzly bear animal
The Ussuri brown bear (U. a. lasiotus), inhabiting Russia, Northern China, Japan, and Korea,[4][7][8] is sometimes referred to as the "black grizzly", although it is no more closely related to North American brown bears than other subspecies of the brown bear around the world.
Classification has been revised along genetic lines.[3] There are two morphological forms of Ursus arctos: the grizzly and the coastal brown bears, but these morphological forms do not have distinct mtDNA lineages.[11]
Brown bears originated in Eurasia and traveled to North America approximately 50,000 years ago,[12][13] spreading into the contiguous United States about 13,000 years ago.[14] The genome of the grizzly bear was sequenced in 2018 and found to be 2,328.64Mb (mega-basepairs) in length, and contain 30,387 genes.[15]
In the 19th century, the grizzly was classified as 86 distinct species. However, by 1928 only seven grizzly species remained,[4] and by 1953, only one species remained globally.[16] However, modern genetic testing reveals the grizzly to be a subspecies of the brown bear (Ursus arctos). Biologist R.L. Rausch found that North America has but one species of grizzly.[2] Therefore, everywhere it is the "brown bear"; in North America, it is the "grizzly", but these are all the same species, Ursus arctos.
Coastal grizzlies, often referred to by the popular but geographically redundant synonym of "brown bear" or "Alaskan brown bear" are larger and darker than inland grizzlies, which is why they, too, were considered a different species from grizzlies. Kodiak Grizzly Bears were also at one time considered distinct. Therefore, at one time there were five different "species" of brown bear, including three in North America.[18]
In North America, grizzly bears previously ranged from Alaska down to Mexico and as far east as the western shores of Hudson Bay;[12] the species is now found in Alaska, south through much of western Canada, and into portions of the northwestern United States (including Washington, Idaho, Montana and Wyoming), extending as far south as Yellowstone and Grand Teton National Parks.[24] In Canada, there are approximately 25,000 grizzly bears occupying British Columbia, Alberta, the Yukon, the Northwest Territories, Nunavut, and the northern part of Manitoba.[12]
An article published in 1954 suggested they may be present in the tundra areas of the Ungava Peninsula and the northern tip of Labrador-Quebec.[25] 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.[12] However, population size has since significantly decreased due to hunting and habitat loss. In 2008, it was estimated there were 16,000 grizzly bears. A revised Grizzly bear count in 2012 for British Columbia was 15,075.[26] Population estimates for British Columbia are based on hair-snagging, DNA-based inventories, mark-and-recapture, and a refined multiple regression model.[27] In 2003, researchers from the University of Alberta spotted a grizzly on Melville Island in the high Arctic, which is the most northerly sighting ever documented.[28][29]
Around 60,000 wild grizzly bears are located throughout North America, 30,000 of which are found in Alaska.[12] and up to 29,000 live in Canada. The Alaskan population of 30,000 individuals is the highest population of any province / state in North America. Populations in Alaska are densest along the coast, where food supplies such as salmon are more abundant.[30] The Admiralty Island National Monument protects the densest population: 1,600 bears on a 1,600 square-mile island.[31] The majority of Canada's grizzlies live in British Columbia.[32]
In the North Cascades ecosystem of northern Washington, grizzly bear populations are estimated to be fewer than 20 bears, but there is a longterm management plan to reintroduce the bears to North Cascades National Park.[36]
The grizzly bear's original range included much of the Great Plains and the southwestern states, but it has been extirpated in most of those areas. Combining Canada and the United States, grizzly bears inhabit approximately half the area of their historical range.[12]
Although the once-abundant California grizzly bear appears prominently on the state flag of California and was the symbol of the Bear Flag Republic before the state of California's admission to the Union in 1850, the subspecies or population is currently extinct. The last known grizzlies in California were killed in the Sierra foothills east of Fresno in the early 1920s.[37]
The killing of the last grizzly bear in Arizona in 1936 at Escudilla Mountain is included in Aldo Leopold's Sand County Almanac.[38] There has been no confirmed sighting of a grizzly in Colorado since 1979.[39]
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, European countries, some areas of Canada, and in all of the United States. However, it is expected that repopulating its former range will be a slow process, due to various reasons, including the bear's slow reproductive habits and the effects of reintroducing such a large animal to areas prized for agriculture and livestock.
In preparation for winter, bears can gain approximately 180 kg (400 lb), during a period of hyperphagia, before going into hibernation.[43] The bear often waits for a substantial snowstorm before it enters its den: such behavior lessens the chances that predators will find the den. The dens are typically at elevations above 1,800 meters (5,900 ft) on north-facing slopes.[44] There is some debate among 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.[45] Although inland or Rocky Mountain grizzlies spend nearly half of their life in dens, coastal grizzlies with better access to food sources spend less time in dens. In some areas where food is very plentiful year round, grizzly bears skip hibernation altogether.[46]
Except for females with cubs,[47] grizzlies are normally solitary, active animals, but in coastal areas, grizzlies gather around streams, lakes, rivers, and ponds during the salmon spawn. Females (sows) produce one to four young (usually two) that are small and weigh only about 450 g (16 oz) at birth. A sow is protective of her offspring and will attack if she thinks she or her cubs are threatened.
Grizzly bears have one of the lowest reproductive rates of all terrestrial mammals in North America.[48] This is due to numerous ecological factors. Grizzly bears do not reach sexual maturity until they are at least five years old.[12][49] 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.[50] On average, females produce two cubs in a litter[49] and the mother cares for the cubs for up to two years, during which the mother will not mate.[12]
The average lifespan for a male is estimated at 22 years, with that of a female being slightly longer at 26.[54] Females live longer than males due to their less dangerous life; they do not engage in seasonal breeding fights as males do. The oldest known wild inland grizzly was about 34 years old in Alaska; the oldest known coastal bear was 39,[55] but most grizzlies die in their first year of life.[56] Captive grizzlies have lived as long as 44 years.[57]
They have a tendency to chase fleeing animals,[58] and although it has been said anecdotally that grizzly bears (Ursus arctos horribilis) can run at 56 km/h (35 mph), the maximum speed reliably recorded at Yellowstone is 48 km/h (30 mph).[59] In addition, they can climb trees.[58]
Although grizzlies are of the order Carnivora and have the digestive system of carnivores, they are normally omnivores: their diets consist of both plants and animals. They have been known to prey on large mammals, when available, such as moose, elk, caribou, white-tailed deer, mule deer, bighorn sheep, bison, and even black bears, though they are more likely to take calves and injured individuals rather than healthy adults. Grizzly bears 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 inland individuals. Grizzly bears also readily scavenge food or carrion left behind by other animals.[60] Grizzly bears will also eat birds and their eggs, and gather in large numbers at fishing sites to feed on spawning salmon. They frequently prey on baby deer left in the grass, and occasionally they raid the nests of raptors such as bald eagles.[61]
Coastal Canadian and Alaskan grizzlies are larger than those that reside in the Rocky Mountains. This is due, in part, to the richness of their diets. In Yellowstone National Park in the United States, the grizzly bear's diet consists mostly of whitebark pine nuts, tubers, grasses, various rodents, army cutworm moths, and scavenged carcasses.[62] None of these, however, match the fat content of the salmon available in Alaska and British Columbia. With the high fat content of salmon, it is not uncommon to encounter grizzlies in Alaska weighing 540 kg (1,200 lb).[63] Grizzlies in Alaska supplement their diet of salmon and clams with sedge grass and berries. In areas where salmon are forced to leap waterfalls, grizzlies gather at the base of the falls to feed on and catch the fish. Salmon are at a disadvantage when they leap waterfalls because they cluster together at their bases and are therefore easier targets for the grizzlies.[64] Grizzly bears are well-documented catching leaping salmon in their mouths at Brooks Falls in Katmai National Park and Preserve in Alaska. They are also very experienced in chasing the fish around and pinning them with their claws.[65] At such sites such as Brooks Falls and McNeil Falls in Alaska, big male grizzlies fight regularly for the best fishing spots.[66] Grizzly bears along the coast also forage for razor clams, and frequently dig into the sand to seek them.[67] During the spring and fall, directly before and after the salmon runs, berries and grass make up the mainstay of the diets of coastal grizzlies.[68] 041b061a72