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

Map: American bison range

American Bison Range

Fast Facts

Type:
Mammal
Diet:
Herbivore
Average life span 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)
Group name:
Herd
Did you know?
The bison's thick, shaggy coat is so well insulated that snow can settle on its back without melting.
Size relative to a 6-ft (2-m) man:
Illustration: American bison compared with adult man

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.

Mammal Features

  • Photo: Close-up of an African lion

    Animal Conservation

    Find out what National Geographic Society is doing to save animals all over the world, and learn what you can do to help.

  • hawaiian-monk-critter-cam.jpg

    Crittercam Helps Study Rare Species

    The Hawaiian monk seal is one of the oldest species of seal on the planet. But their tenure in paradise is perilously close to its end; only about 1,100 seals remain in the wild.

  • Masai Mara Lion

    Lions Quiz

    The king of cats rules with a roar and a fierce bite. What else do you know about this top predator?

  • Photo: Lion bares his teeth

    Cause an Uproar

    Big cats are quickly disappearing. Now is the time to act. Cause an uproar to save big cats today.

Photos

  •  Picture of a Malayan tiger

    Pictures: Tiger Subspecies

    Scientists estimate only about 3,000 wild tigers are left in the entire world. Meet the subspecies and see what threats each is facing.

See more animal photos »

From the Magazine

  • Photo of the lions of the Vumbi pride.

    The Surprising Lives of Lions

    In case you missed it: See these breathtaking videos and photos from inside a wild Serengeti pride.

  • Photo: Two adult preen, Ireland

    Gannets Pictures

    Champion divers but clumsy landers, doting parents but hostile neighbors—northern gannets abound in contradictions.