"Last of the Buffalo" by Albert Bierstadt. Property of the Library of Congress (Geist, 36).


Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Genus: Bison
Species: bison (Nature Works)

Physical Appearance:

American bison are the heaviest land animals in North America (National Geographic). Males can grow up to 6 feet from hoof to shoulder, and weigh 1000-2000 lbs. Females can grow up to 5 feet from hoof to shoulder, and weigh 800-1000 lbs. American bison have brown hair, a mane, horns, a big head, hooves, and a tail with a tuft on the end (New Hampshire Public Television). 

"Massive American Bison by Lake Yellowstone." (Animal Photos!).

Population and Range--A Tale of Human Interaction:

Today, there are approximately 500,000 bison in North America. However, most are not pure bison, having been bred with cattle for ranching purposes (Defenders of Wildlife).

In the 1700s and early 1800s, American bison covered much of the United States and Canada. They were observed in the wild as far south as Mississippi and Georgia, as far east as Maryland, as far West as California’s northeast Lassen County, and far up into the Prairie Provinces of Canada (Geist, 62-3, 97). Their large population and range was likely a result of a dramatic ecological shift in the 15th and 16th centuries. It is theorized that the depletion of the American Indian population—bison’s primary predator at the time --by disease after the arrival of Europeans in America, resulted in a surge and spread in the bison population (Geist, 70).

Throughout the course of the 19th century, hunting by primarily white settlers reigned in the American bison population. In Canada, bison were hunted mostly for their furs. In the United States, meanwhile, bison were explicitly targeted by white settlers and the American military as a way to “win the West” from American Indians, as Plains’ Indians’ culture and livelihood centered around American bison (Geist, 96-7).

The construction of the Transcontinental Railroad also played a role in depleting the American bison population--separating those that roamed north of the railroad from those that roamed south of the railroad (Geist, 97).

Today, the population of American bison is almost entirely limited to national parks and refuges (New Hampshire Public Television). Most notably, Yellowstone National Park hosts the largest free-roaming plains bison population, while Wood Buffalo National Park hosts the largest free-roaming wood bison population (Defenders of Wildlife).

Although there are significant efforts to preserve the last remaining pure American bison, the population is not without threats. In Yellowstone National Park bison face threats from farmers in Montana, who fear that the animal will spread brucellosis to their cattle, although no instances of brucellosis have been recorded in wild bison. Wood bison have been listed as endangered under the Endangered Species Act, and plains bison are under review by the same Act (Defenders of Wildlife). 

A pile of buffalo skulls in Detroit, waiting to be processed for manufacturing. Property of Detroit Public Library. (Geist, 97).



American bison graze, eating mostly wild grasses and sedges, but also occasionally berries and lichen. In the winter, bison clear away snow with their heads and hooves to find plants to eat (Nature Works). Bison eat continuously—wandering great distances rather than over-grazing one area (Defenders of Wildlife). They spend most of their day chewing on cud and are most active in early morning or late afternoon (New Hampshire Public Television).



                Bison mating season lasts from June to September, with the peak period in July and August (Defenders of Wildlife). Bulls will compete with each other for                 females by ramming their heads into each other, locking horns, and jutting each other with their horns (Geist, 55).

                Tending and Mating:

                When a bull wins a rutting competition, he will then tend the female. He does this by staying between the herd and the female, who will walk away if she                 isn’t interested. The process of tending can last from a few minutes to a few days (New Hampshire Public Television).


                Calves are born between April and May (Defenders of Wildlife). A female reaches child-bearing age around 2 or 3 years, while a bull is not yet ready to                    mate until the age of 6 years (New Hampshire Public Television). Females bear one calf per litter (Defenders of Wildlife). They go into isolation to bear                    their young (New Hampshire Public Television). A calf can typically walk shortly after birth (Geist, 56).


Wallowing is an action characteristic of bison. It is theorized that bison wallow to drive off flies. However, this action is also intensely social. A bison will wallow by rubbing its head into the ground. Frequently, male bison do this before rivals during mating season. If one bull begins to wallow, a more dominant bull will come and take his place. Frequently, wallowing holes can become quite large, and were characteristic of the Western landscape during the heydays of the American bison (Geist, 52).


Females and their young live in groups of about 20. Males can live in groups of up to 20, smaller groups, or individually. Each group typically has a dominant male or female (New Hampshire Public Television).


“American Bison: Bison bison.” 2011. Website for National Geographic:  Animals Nat Geo Wild. Accessed 11.22.11. http://animals.nationalgeographic.com/animals/mammals/american-bison/

“American Bison: Bison bison.” 2011. Website for New Hampshire Public Television: Nature Works. Accessed 11.22.11. http://www.nhptv.org/natureworks/americanbison.htm

“Bison: Bison bison.” 2011. Website for Defenders of  Wildlife. Accessed 11.22.11.  http://www.defenders.org/wildlife_and_habitat/wildlife/bison.php

Geist, Valerius. Buffalo Nation: History and Legend of the American Bison. Stillwater: Voyageur, 1996.

"Massive American Bison by Lake Yellowstone." 2011. Animal Photos! Accessed 12.06.11. http://animalphotos.info/a/topics/animals/mammals/buffalo/