The American Bison (Bison bison) is a North American species of bison, also commonly known as the American Buffalo. "Buffalo" is somewhat of a misnomer for this animal, as it is only distantly related to either of the two "true buffaloes", the Asian Buffalo (or "Water Buffalo") and the African Buffalo. However, "bison" is a Greek word meaning ox-like animal, while "buffalo" originated with the French fur trappers who called these massive beasts boeufs, meaning ox or bullock. So both names, "bison" and "buffalo," have a similar meaning. In reference to this animal, the term "buffalo," which dates to 1635, has a much longer history than the term "bison," which was first recorded in 1774. The American Bison is more closely related to the Wisent or European Bison. These bison once inhabited the grasslands of North America in massive herds; their range roughly formed a triangle between the Great Bear Lake in Canada's far northwest, south to the Mexican states of Durango and Nuevo León, and east along the western boundary of the Appalachian Mountains. The two subspecies include the Plains Bison (Bison bison bison), smaller in size and with a more rounded hump, and the Wood Bison (Bison bison athabascae), which is the larger of the two and with a taller, square hump. Wood Bison is one of the largest species of cattle in the world, surpassed only by the Asian gaur and Wild Asian Water Buffalo. It is the largest extant land animal in North America.
bison has a shaggy, long, dark brown winter coat, and a lighter weight, lighter brown summer coat. Bison can reach up to 2 meters (6.6 ft) tall, 3 meters (10 ft) long, and weigh 400 kg (900 lb) to 1,000 kg (2,200 lb). As typical in ungulates, the male bison is slightly larger. The biggest specimens on record have weighed as much as 1,130 kilograms (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 are herbivores, grazing on the grasses and sedges of the North American prairies. They eat in the morning and evening, and rest during the day. Bison mate in August and September; gestation is 285 days. 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 approximately 15 years in the wild and up to 25 years in captivity. Juveniles are lighter in color than mature bison for the first three months of life. One very rare condition is the white buffalo, where the calf turns entirely white. White bison are considered sacred by many Native Americans.
Although superficially similar, there are a number of physical and behavioural differences between the American and European bison. The American species has 15 ribs, while the European bison has 14. The American bison has four lumbar vertebrae, while the European has five. Adult American bison are not as rangy in build, and have shorter legs. American bison tend to graze more, and browse less than their European cousins, due to their necks being set differently. Compared to the American bison, the nose of the European species is set further forward than the forehead when the neck is in a neutral position. The body of the American bison is hairier, though its tail has less hair than that of the European bison. The horns of the European bison point forward through the plane of their faces, making them more adept at fighting through the interlocking of horns in the same manner as domestic cattle, unlike the American bison which favours charging. American bison are more easily tamed than their European cousins, and breed with domestic cattle more readily.
ison are polygamous. Dominant bulls maintain a small harem of females for mating. Individual bulls "tend" females until allowed to mate, by following them around and chasing away rival males. Homosexual behavior—including courtship and mounting between bulls—is common among bison. The Mandan nation Okipa festival concludes with a ceremonial enactment of this behavior, to "ensure the return of the buffalo in the coming season." Inter-sexual bison also occur. The Lakota refer to them as pte winkte—pte meaning bison and winkte designating two-spirit—thereby drawing an explicit parallel between transgenderism in animals and people. In some areas, wolves are a major predator of bison. Wolf predation typically peaks in late spring and early summer, with attacks usually being concentrated on cows and calves. Observations have shown that wolves actively target herds with calves over ones without. Bison display five apparent defense strategies in protecting calves from wolves. These include running to a cow, running to a herd, running to the nearest bull, run in the front or center of a stampeding herd, and to enter water bodies such as lakes or rivers. When fleeing wolves in open areas, cows with young calves take the lead, while bulls take to the rear of the herds, to guard the cows' escape. The length of a bison hunt varies, ranging from lasting a few minutes to 11 hours. Bison typically ignore wolves not displaying hunting behavior. Packs specialising in bison tend to have a greater number of males, as their superior size to the females allows them to wrestle bison to the ground more effectively. The Grizzly Bear can also pose a threat to calves and sometimes adult bison.