Grizzly, North American brown bear
The Grizzly bear (Ursus arctos horribilis) is a population or subspecies of the Brown bear that is found in North America. Native American tribes living among Brown bears often view them with a mixture of awe and fear. North American brown bears have at times been so feared by the Natives that they were rarely hunted by them, especially when alone. Nowadays many people come to Alaska to watch the bears and observe their habits. Some of the best bear viewing in the world occurs in coastal areas of the Alaska Peninsula, including in Lake Clark National Park and Preserve, Katmai National Park and Preserve, and the McNeil River State Game Sanctuary and Refuge. Here bears gather in large numbers to feast on concentrated food sources, including sedges in the salt marshes, clams in the nearby tidal flats, salmon in the estuary streams, and berries on the neighboring hillsides.
Although variable in color from blond to nearly black, Grizzly bear fur is typically brown with darker legs and commonly white or blond-tipped fur on the flank and back. They have short, rounded ears and adult bears have a pronounced muscular hump on their shoulders. The front claws of Grizzly bears measure about 51-102 mm (2-4 in) in length.
In North America, Grizzly bears are 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. In Canada, they occupy British Columbia, Alberta, the Yukon, the Northwest Territories, Nunavut, and the northern part of Manitoba. Grizzly bears inhabit temperate forests and also prefer semiopen country, with a scattering of vegetation that can allow them a resting spot during the day.
Grizzlies are solitary animals, except for females with cubs; however, in coastal areas, they gather around streams, lakes, rivers, and ponds during the salmon spawn. Grizzly bears hibernate for 5-7 months each year (except where the climate is warm - the California grizzly did not hibernate). During this time, females give birth to their cubs, who then consume milk from their mother and gain strength for the remainder of the hibernation period. To prepare for hibernation, grizzlies must prepare a den and consume an immense amount of food because they do not eat during hibernation. The males’ hibernation ends in early to mid-March, while females emerge in April or early May. Grizzly bears have a tendency to chase fleeing animals; the maximum speed reliably recorded at Yellowstone is 48 km/h (30 mph). In addition, they can climb trees. In general, Brown bears are often described as nocturnal. However, they frequently peak in activity in the morning and early evening hours. They usually occur over vast home ranges but, they are not highly territorial. Males always cover more area than females each year. In order to communicate with each other Grizzly bears use facial expressions and various vocalizations. They huff when are tense and woof when alarmed. Growls and roars are made in aggression. Their roaring is described as "thunderous" and can travel 2 km (1.2 mi). Mothers and cubs wanting physical contact will bawl, which is heard as waugh!, waugh!.
Grizzly bears are omnivores and their diets consist of both plants and animals. They 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. Grizzly bears also readily scavenge food or carrion left behind by other animals. They will also eat birds and their eggs. They frequently prey on baby deer left in the grass, and occasionally they raid the nests of raptors such as Bald eagles.
In general, Brown bears are serially monogamous and remain with the same mate from a couple of days to a couple of weeks. During this time, the male competes with other males in the area, protecting the female from them. Grizzly bears have one of the lowest reproductive rates of all terrestrial mammals in North America. Once mated with a male in the summer, the female delays embryo implantation until hibernation. Litter size varies between 1 and 4 cubs. Cubs are always born in the mother's winter den while she is in hibernation. Female grizzlies are fiercely protective of their cubs, being able to fend off predators including larger male bears. Cubs feed entirely on their mother's milk until summer comes, after which they still drink milk but begin to eat solid foods. Cubs gain weight rapidly during their time with the mother - their weight will have increased from 4.5 to 45 kg (9.9 to 99.2 lb) in the 2 years spent with the mother. Mothers may see their cubs in later years but both avoid each other. Young Grizzly bears usually do not reach reproductive maturity until they are at least 5 years old.
The main threats to these animals include habitat loss and fragmentation through the extension of human habitat: highways and settlements together with the development of agriculture bring to decrease in their habitat. 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. Other threats to these animals include hunting as many people come to Alaska to bear-hunt and they are also poached for their paws and gallbladders which have high commercial value.
According to IUCN Red List, the total population size of the Grizzly bear is estimated to be 33,000 individuals in the U.S. (mainly in Alaska) and 25,000 individuals in Canada. In North America, the southern fringe has isolated subpopulations ranging in size from near 700 bears in and around Yellowstone National Park to approximately 25 individuals in the Cabinet Mountains of Montana and even less, likely 10 bears, in some southern areas of British Columbia. Currently, the Brown bear species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are stable.
The Grizzly bear plays an important role in the local ecosystem. First of all, they act as seed distributors in their habitats. After the grizzly consumes the fruit, the seeds are excreted and thereby dispersed in a germinable condition. 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. 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 (1,600 ft) of the stream where the salmon have been obtained contains nitrogen originating from salmon on which the bears preyed. Grizzlies also 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 in Wyoming in the United States 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. When grizzly bears fish for salmon along the coasts of Alaska and British Columbia, they often only eat the skin, brain, and roe of the fish. In doing so, they provide a food source for gulls, ravens, and foxes, all of which eat salmon as well; this benefits both the bear and the smaller predators.
