Wood bison in the context of "Bison bison"

The American bison (Bison bison; pl.: bison), commonly known as the American buffalo, or simply buffalo (not to be confused with true buffalo), is a species of bison that is endemic (or native) to North America. It is one of two extant species of bison, along with the European bison. Its historical range circa 9000 BC is referred to as the great bison belt, a tract of rich grassland spanning from Alaska south to the Gulf of Mexico, and east to the Atlantic Seaboard (nearly to the Atlantic tidewater in some areas), as far north as New York, south to Georgia, and according to some sources, further south to northern Florida, with sightings in North Carolina near Buffalo Ford on the Catawba River as late as 1750.

Two subspecies or ecotypes have been described: the plains bison (B. b. bison), smaller and with a more rounded hump; and the wood bison (B. b. athabascae), the larger of the two and having a taller, square hump. Furthermore, the plains bison has been suggested to consist of a northern plains (B. b. montanae) and a southern plains (B. b. bison) subspecies, bringing the total to three. However, this is generally not supported. The wood bison is one of the largest wild species of extant bovid in the world, surpassed only by the Asian gaur. Among extant land animals in North America, the bison is the heaviest and the longest, and the second tallest after the moose.

A bison (pl.: bison) is a large bovine in the genus Bison (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant and numerous extinct species are recognised.

Of the two surviving species, the American bison, B. bison, found only in North America, is the more numerous. Although colloquially referred to as a buffalo in the United States and Canada, it is only distantly related to the true buffalo. The North American species is composed of two subspecies, the Plains bison, B. b. bison, and the generally more northern wood bison, B. b. athabascae. A third subspecies, the eastern bison (B. b. pennsylvanicus) is no longer considered a valid taxon, being a junior synonym of B. b. bison. Historical references to "woods bison" or "wood bison" from the Eastern United States refer to this synonym animal (and to their eastern woodland habitat), not to B. b. athabascae, which was not found in the region. Its European kind B. bonasus or wisent —also 'zubr' or colloquially 'European buffalo'— is found in Europe and the Caucasus, reintroduced after being extinct in the wild.

The plains bison (Bison bison bison) is one of two subspecies/ecotypes of the American bison, the other being the wood bison (B. b. athabascae). A natural population of plains bison survives in Yellowstone National Park (the Yellowstone Park bison herd consisting of an estimated 4,800 bison). Multiple smaller reintroduced herds of bison in many ranges within the midwestern and western United States (including Alaska, but not Hawaii) as well as southern portions of the Canadian Prairies.

Wood Buffalo National Park is the largest national park of Canada at 44,741 km (17,275 sq mi). It is in northeastern Alberta and the southern Northwest Territories. Larger in area than Switzerland, it is the second-largest national park in the world. The park was established in 1922 to protect the world's largest herd of free-roaming wood bison. They became hybridized after the introduction of plains bison. The population is currently estimated at 3,000. It is one of two known nesting sites of whooping cranes.

The park ranges in elevation from 183 m (600 ft) at the Little Buffalo River to 945 m (3,100 ft) in the Caribou Mountains. The park headquarters is in Fort Smith, with a smaller satellite office in Fort Chipewyan, Alberta. The park contains one of the world's largest fresh-water deltas, the Peace-Athabasca Delta, formed by the Peace, Athabasca and Birch rivers.