American Bison

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Revision as of 03:25, 20 June 2009

The American Bison is a bovine mammal, also commonly known as the American Buffalo, or simply buffalo, something of a misnomer as it is only distantly related to either of the two "true buffalos": the Water Buffalo and the African Buffalo.

With their huge bulk, Wood Bison – which are the largest subspecies in North America – are only surpassed in size by the massive Asian Gaur and wild water buffalo, both of which are found mainly in India. The bison inhabited the Great Plains of the United States and Canada in massive herds, ranging from the Great Slave Lake in Canada's far north to Mexico in the south, and from eastern Oregon almost to the Atlantic Ocean, taking its subspecies into account. Its two subspecies are the Plains Bison (Bison bison bison), distinguished by its smaller size and more rounded hump, and the Wood Bison (Bison bison athabascae), distinguished by its larger size and taller square hump.

Description

Bison have a shaggy, dark brown winter coat, and a lighter weight, lighter brown summer coat. Bison can reach up to 2 metres (6½ ft) tall, 3 metres (10 ft) long and weigh 900 to 2,000 lbs. The biggest specimens on record have weighed as much as 1140 kg (2,500 lb). The heads and forequarters are massive, and both sexes have short, curved horns, which they use in fighting for status within the herd and for defense. Bison mate in August and September; a single reddish-brown calf is born the following spring, and it nurses for a year. Bison are mature at three years of age, and have a life expectancy of 18 to 22 years in the wild and 35 to 40 years in captivity. Bison can jump up to 6 feet high and run up to 40 mph, a fact that comes as a surprise to those familiar with docile domesticated cattle.

One very rare condition results in the white buffalo, where the calf turns entirely white. It is not to be confused with albino, since white bison still possess pigment in the skin, hair, and eyes. White bison are considered sacred by many Native Americans.

Due to its size and the protection afforded by living in a herd, the bison have few enemies besides humans. Grizzly bears and wolves may attempt to attack young calves or subadults, but only in the dead of winter when the herd cannot expend the energy to protect stragglers. A wolf pack can also take down an adult bison, wolves frequently test even the largest bison for weaknesses, usually several wolves may pursue a bison and attempt to bring it down after the bison has succumbed to exhaustion or wounds from the wolves' deadly jaws. The only other threat, other than hunting by humans, that leads to the depletion of wild bison is interbreeding with domestic bovines. In fact, only a small number of bison herds found in North America today are pure breed bison.

Dangers

Bison are among the most dangerous animals encountered by visitors to the various U.S. National Parks, especially Yellowstone National Park. Although they are not carnivorous, they will attack humans if provoked. They appear slow because of their lethargic movements, but they can easily outrun humans—they have been observed running as fast as 35 miles per hour (56 kilometres per hour). Between 1978 and 1992, over four times as many people in Yellowstone National Park were killed or injured by bison as by bears (12 by bears, 56 by bison). Bison also have the unexpected ability, given the animal's size and body structure, to leap over a standard barbed-wire fence.