Natural Histories

photograph of a Sunda Pangolin

American Bison

Bison bison


American bison are large mammals with a distinctive shoulder hump and large forehead. Both male and female American bison have sharp black horns curving upward and inward. Male American bison can grow to be 3.6-3.8 m in length with a shoulder height of 1.67-1.86 m, while the females grow to be 2.13-3.18 m long with a shoulder height of 1.52-1.57 m. This species has brown fur that is slightly darker in the head and back. The coat of an American bison is longer in the front of the animal than the rear; this is especially noticeable in males. Young American bison have a reddish coat, which turns brown after four months.


This species can be found on private and protected lands in the western United States and Canada. Herds of American bison are located in Yellowstone National Park, Wyoming and Wood Buffalo Park in the Northwest Territory, Canada. American bison prefer grasslands and open savannas but can also be found in boreal habitats and even semi-desert habitats if there is suitable grazing.

Feeding Behavior and Diet

American bison graze year-round, feeding on grasses as well as other vegetation. This species must have ingest water daily and consume 1.6% of their body mass in food every day.


Breeding season for American bison occurs in late June until September. Dominant bulls (males) follow a small group of females and drive away rival males as a way to restrict mating access to the females by fighting other bulls. Females produce 1-2 calves 285 days after mating. Calving season is usually from mid-April until the end of May; occasionally some births will occur in the late summer. Young are nursed for 7-8 months and are fully weaned after one year. Female American bison become sexually mature after 2-3 years while males do not reach sexual maturity until reaching three years of age.

Months and Times of Activity

This species grazes in loose groups during the day.

Special Features, Stories, Relationships

  • American bison are very good swimmers and runners–this species can reach speeds of 62 km/hr.
  • American bison are gregarious, traveling in groups and divided by sex and age. Cow groups consist of females, males under three years old, and a few older males. Some males live in groups of up to 30 individuals while other males are solitary. Males are ranked based on mating rights with higher ranking males breeding with more cows (females).
  • The American bison was once found from Alaska to northern Mexico in pre-Columbian times with a population of 60 million. Herds of bison suffered massive slaughters by humans as a government political act to destroy the livelihood of the Plains Indians. This caused an extermination of the wild American bison and reducing the population to less than 1000 by 1890. They are now only found in private and protected lands. This species is listed under CITES- Appendix I and the subspecies B. b. athabascae is listed as an endangered species by the U.S. Endangered Species Act.
  • To read legends featuring this animal go to;
  • Children’s book featuring this animal: AMERICAN BISON by Steve Potts


Newell, Toni L., and Anna B. Sorin. "Bison Bison American Bison." Animal Diversity Web. Michigan University, 2003. Web. 04 Apr. 2013