The English word "bear" comes from Old English bera and belongs to a family of names for the bear in Germanic languages, such as Swedish björn, also used as a first name. They moved between 25 m (82 ft) and 2,698 m (8,852 ft) daily in the dry season and increased their daily movement to 4,143 m (13,593 ft) in the wet season. Panda care in zoos has been perfected since the 1950s and earlier. [42] To prepare for hibernation, grizzlies must prepare a den, and consume an immense amount of food as they do not eat during hibernation. [150] 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. [44] Female bears give birth during the hibernation period, and are roused when doing so. Their front paws are flexible enough to grasp fruit and leaves. [127], Bears have been hunted for sport, food, and folk medicine. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. In 1963 Rausch reduced the number of North American subspecies to one, Ursus arctos middendorffi. [106] If they have stored enough body fat, their muscles remain in good condition, and their protein maintenance requirements are met from recycling waste urea. These bears have very low birth rates, and only raise a single cub in the wild, even if twins are born. The Ussuri brown bear (U. a. lasiotus), inhabiting Russia, Northern China, Japan, and Korea,[3][6][7] is sometimes referred to as the "black grizzly", although it is a different subspecies from the bears in America. [131] In many Native American cultures, the bear is a symbol of rebirth because of its hibernation and re-emergence. [118] Mothers defending cubs are the most prone to attacking, and are responsible for 70% of humans killed by grizzlies. [citation needed] Fertility lasts until 15 years of age. [65] In autumn, some bear species forage large amounts of naturally fermented fruits, which affects their behavior. [45][46] Larger species tend to show increased levels of sexual dimorphism in comparison to smaller species. In almost all cases, avoiding surprise encounters is the best defense, as black bears prefer to avoid people. Emeritus Professor of Zoology, Southern Illinois University at Carbondale. Ursavinae [15] There has been various morphological evidence linking amphicynodontines with pinnipeds, as both groups were semi-aquatic, otter-like mammals. Bark may be spread around to draw attention to the marking post. Within the United States, the U.S. At Brooks Camp, a famous site exists where grizzlies can be seen catching salmon from atop a platform—it can be even viewed online from a cam. The brown bear can live an average of 25 years. Home ranges typically are larger where food is less abundant and smaller where food is plentiful. [100], The grizzly bear has several relationships with its ecosystem. One such relationship is a mutualistic relationship with fleshy-fruit bearing plants. [132] These are estimates because bears move in and out of these areas, and it is therefore impossible to conduct a precise count. The giant panda has a special bone formation of the forefoot that functions as a sixth digit; it is opposable to the other five and thus is useful in handling bamboo. The coat consists of long guard hairs, which form a protective shaggy covering, and short dense hairs which form an insulating layer trapping air close to the skin. 2009", "Grizzly Bear Recovery. Adults range from 1.5 to 1.8 metres (5 to 6 feet) in length and weigh 90–270 kg (200–600 pounds). Grizzly bears do not reach sexual maturity until they are at least five years old.