American Bison (Bison bison)

Mammal Grazer Conservation recovery

Overview

The American bison (Bison bison) is the largest land mammal in North America and an icon of the continent's grasslands. Heavy-bodied and surprisingly agile, bison are grazing herd animals whose history is closely tied to the ecology of the Great Plains and to one of the best-known conservation recoveries in modern times.

Two subspecies are generally recognised: the plains bison and the larger wood bison of more northern forested regions. Bison shape grasslands through grazing, wallowing, and trampling, influencing plant communities and other wildlife.

Conservation note: after near-extinction in the 19th century, bison have recovered through protected and managed herds, though much of the population today is managed rather than fully wild. For current conservation status of wild and conservation herds, verify at iucnredlist.org.

Classification

Bison are bovids — the same family as cattle, buffalo, antelope, sheep, and goats. The closely related European bison or wisent (Bison bonasus) is a separate species.

Habitat & Range

Plains bison are animals of open grassland, prairie, and sagebrush, while wood bison occupy more northern meadow and boreal forest mosaics. Today bison occur largely in national parks, reserves, tribal lands, and managed herds across parts of North America, rather than across their full historical range.

Diet & Feeding

Bison are grazers, feeding primarily on grasses and sedges. As ruminants, they ferment plant material in a multi-chambered stomach, allowing them to extract nutrients from fibrous vegetation. Their grazing patterns help maintain grassland structure and diversity.

Behavior & Social Life

Bison are social and usually live in herds, with cows, calves, and younger animals forming groups that bulls join especially during the rut. The breeding season features bellowing, displays, and sparring between bulls. Despite their bulk, bison are fast runners and capable jumpers and should always be given a wide berth in the wild.

A characteristic behaviour is wallowing — rolling in dust or mud — which may help with shedding, parasites, and thermoregulation and leaves shallow depressions that persist in the landscape.

Appearance & Recognition

Bison are recognised by their massive forequarters, a prominent shoulder hump, a large low-slung head, and a shaggy dark-brown coat that is thickest over the head, neck, and shoulders, forming a beard and mane. Both sexes carry short, curved horns. The contrast between the heavy front end and the leaner hindquarters gives bison their distinctive silhouette.

Human Interaction & Conservation

Bison hold deep cultural significance for many Indigenous peoples of North America and are central to grassland restoration efforts. Conservation today balances genetics, disease management, available habitat, and the relationship between conservation herds and managed or commercial herds. Current status and population information should be drawn from authoritative conservation sources.

More photos of the bison