American Bison
Bison bison

Photo: Close-up of a bison
With their large, sharp horns, bison are formidable foes. During mating season, bulls fight for the right to breed with harems of cows, but rarely duel to the death.
Photograph by Sam Abell
Map: Locator map for the American bison
 American Bison range

Fast Facts

Type: Mammal
Diet: Herbivore
Average lifespan in the wild: 12 to 20 years
Size: Head and body, 7 to 11.5 ft (2.1 to 3.5 m); Tail 19.75 to 23.5 in (50 to 60 cm)
Weight: 930 to 2,200 lbs (422 to 998 kg)
Did you know? The bison's thick, shaggy coat is so well insulated that snow can settle on its back without melting.

Bison, symbolic animals of the Great Plains, are often mistakenly called buffaloes. By any name, they are formidable beasts and the heaviest land animals in North America.

Bison stand some 5 to 6.5 feet (1.5 to 2 meters) tall at the shoulder, and can tip the scales at over a ton (907 kilograms). Despite their massive size, bison are quick on their feet. When the need arises they can run at speeds up to 40 miles (65 kilometers) an hour. They sport curved, sharp horns that may grow to be two feet (61 centimeters) long.

These large grazers feed on plains grasses, herbs, shrubs, and twigs. They regurgitate their food and chew it as cud before final digestion.

Females (cows) and adult males (bulls) generally live in small, separate bands and come together in very large herds during the summer mating season. Males battle for mating primacy, but such contests rarely turn dangerous. Females give birth to one calf after a nine-month pregnancy.

Bison once covered the Great Plains and much of North America, and were critically important to Plains Indian societies. During the 19th century, settlers killed some 50 million bison for food, sport, and to deprive Native Americans of their most important natural asset. The once enormous herds were reduced to only a few hundred animals. Today, bison numbers have rebounded somewhat, and about 200,000 bison live on preserves and ranches where they are raised for their meat.