American bison

American bison. The American bison is a large ungulate native to North America and a keystone species of the Great Plains. Once numbering in the tens of millions, its herds were driven to the brink of extinction in the 19th century before concerted conservation efforts began. Today, it is considered the national mammal of the United States and symbolizes the continent's wilderness heritage.

Description and taxonomy

The species was first formally described by Carl Linnaeus in 1758. Historically, two subspecies are recognized: the larger, wood-adapted wood bison (B. b. athabascae) of northern Canada, and the more numerous plains bison (B. b. bison). They are distinguished from the European bison by their shoulder hump, massive head, and shorter, curvier horns. Adult males, or bulls, can weigh over 900 kilograms, making them the largest terrestrial animals in North America. Their thick, shaggy winter coat is a defining characteristic, shed in the spring to reveal a lighter summer coat.

Habitat and distribution

Historically, their range stretched from the eastern foothills of the Appalachian Mountains to the Rocky Mountains and from the northern reaches of the Great Slave Lake in Canada down into northern Mexico. Their prime habitat was the open and semi-open grasslands of the Great Plains, though the wood bison subspecies inhabited the boreal forests and parklands of Alberta and the Northwest Territories. Following near-extinction, current managed herds are found primarily within protected areas such as Yellowstone National Park, Wind Cave National Park, and the Wood Buffalo National Park in Canada.

Behavior and ecology

They are gregarious animals, forming herds that historically could number in the thousands, particularly during seasonal migrations. Herd structure is matriarchal, with groups of females and their offspring led by an older cow, while bulls often form smaller bachelor groups or live solitarily. Their grazing and wallowing behaviors significantly shape the prairie ecosystem, promoting plant diversity and creating depressions that hold water. Major predators historically included the Plains wolf and the grizzly bear, with calves being particularly vulnerable. The rutting season occurs in late summer, with intense battles between bulls for breeding rights.

Conservation and management

Commercial hunting, encouraged by U.S. policies like the Indian Removal Act and the expansion of railroads such as the Union Pacific Railroad, decimated populations from an estimated 30 million to fewer than 1,000 by the 1880s. Key figures in early conservation included William Temple Hornaday and President Theodore Roosevelt, who helped establish the American Bison Society. Modern recovery involves genetic management to preserve purity from cattle introgression, disease control for ailments like brucellosis, and habitat restoration. Herds are managed by entities like the U.S. Fish and Wildlife Service, Parks Canada, and tribal nations through initiatives like the InterTribal Buffalo Council.

Cultural significance

For millennia, the species was integral to the culture and survival of many Plains Indians nations, including the Lakota people, Cheyenne, and Blackfoot Confederacy, providing food, tools, and spiritual inspiration. Its near-elimination was a deliberate strategy during the American Indian Wars to subjugate these tribes. It appears on the official seal of the U.S. Department of the Interior and is the state mammal of Kansas, Oklahoma, and Wyoming. The 2023 film Killers of the Flower Moon and the artwork of George Catlin depict its historical and cultural centrality. Its designation as the national mammal was signed into law by President Barack Obama in 2016.

Category:Bovines Category:Fauna of the United States Category:Fauna of Canada Category:Symbols of the United States