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American Bison (Bison bison) Fact Sheet: Summary

American Bison (Bison bison)

American Bison (Bison bison) Fact Sheet

American bision

American Bison (Bison bison)

Image credit: Jack Dykinga; released by the Agricultural Research Service, the research agency of the United States Department of Agriculture (ID# K5680-1); made available on Wikimedia Commons. Public domain.


Taxonomy Physical Characteristics

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Artiodactyla (or Cetartiodactyla) (Even-toed hoofed animals: includes pigs, sheep goats, cattle, deer)

Family: Bovidae (cattle, water buffalo, bison, antelopes, goats, sheep and more)

Genus: Bison

Species: Bison bison - American bison

Subspecies: Bison bison bison - American Plains Bison
Subspecies: Bison bison athabascae - Wood Bison

Body Weight
Males: 554-907 kg (1,221-2,000 lb)
Females: 318-545 kg (701-1,202 lb)

Body Length
Male: 3,040-3,800 mm (10-12.5 ft)
Female: 2,130-3180 mm (7.0-10.4 ft)

Tail Length
Male: 330-910 mm (1.1-3.0 ft)
Female: 300-510 mm (1.0-1.7 ft)

Brown, dark brown, or blackish-looking at a distance. Longest hairs on head, beard, and forelegs. Winter coat is wooly fur under coarse, protective guard hairs. Young are lighter in color.

Distribution & Status Behavior & Ecology

Alaska, Canada, Montana to the U.S.-Mexico Border along the Rocky Mountain Range

American Wood Bison: parklands and woodlands
American Plains Bison: grasslands

IUCN Status
Near Threatened (2016 assessment) (Aune et al. 2017)

CITES Appendix
Not listed (as of Aug 2019) (UNEP 2019) 
(Wood bison, B. b. athabascae, deleted in 2017)

Population in Wild
Total population: 31,000 individuals; 11,000-13,000 mature

  • Plains bison: 20,000 individuals
  • Wood bison: 11,000 individuals

Walking, trotting, galloping, jumping. Can run up to 60 km/hr (35 mph).

Activity Cycle
Active during the day. Graze and ruminate. Wallow during the summer.

Social Groups
Gregarious. Fluid groups of females with calves, young males, and possibly 2-3 older males.

Mostly grasses. Sometimes, lichens, mosses, wild oats.

Wolves, humans

Reproduction & Development Species Highlights

Sexual Maturity
Males: about 4-6 years old
Females: about 3-4 years old

285 days, but may vary so females can give birth at the same time

Litter Size
1 calf

Birth Weight
15-25 kg (33-55 lb)

Age at Weaning
6 months

Typical Life Expectancy
Wild populations: 20 years
Managed care: no AZA estimates available

Feature Facts

  • Once roamed in vast herds over North America; nearly exterminated from North America during 1800s and 1900s
  • 2 subspecies: Northern (Wood Bison) and Southern (Plains Bison)
  • Many live on private ranches today
  • Non-territorial; migrate seasonally
  • Males produce very loud bellows
  • Tolerate cold weather extremely well
  • Acute sense of sense and good eyesight
  • Huge wave of domestication in recent decades; concern over genetic modifications and crossbreeding with cattle

About This Fact Sheet

© 2009-2019 San Diego Zoo Wildlife Alliance. Population estimates updated Nov 2018.


How to cite: American Bison (Bison bison) Fact Sheet. c2009-2019. San Diego (CA): San Diego Zoo Wildlife Alliance; [accessed YYYY Mmm dd]. americanbison
(Note: replace YYYY Mmm dd with date accessed, e.g., 2015 Sep 10)


Disclaimer: Although San Diego Zoo Wildlife Alliance makes every attempt to provide accurate information, some of the facts provided may become outdated or replaced by new research findings. Questions and comments may be addressed to

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