Common Name: American Bison
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Genus: Bison
Species: Bison bison

photo M. Noonan

photo M. Noonan

The American bison is the largest land animal in North America. Large bulls can stand 5 to 6 feet at the hump, measure 10 to 12 feet from nose to rump, and weigh up to 2,200 pounds! Bison live from 12 to 15 years in the wild, and can be found living in the plains, prairies, river valleys, and in forests. Their distribution within North America includes Wood Buffalo National Park, Mackenzie Bison Sanctuary, and Slave River Lowlands in Northwest Territories, Canada, and in Yellowstone National Park, Wyoming. There are also a few small free-ranging herds in Alaska, Northeast British Columbia, Northwest Saskatchewan, and Northwest Territories. One can also find many smaller herds in fenced areas. The bison has a thick brown fur coat that keeps the animal warm in the harsh winters of the plains. It gets rid of this coat in the spring to form a lighter coat for the warmer weather. Bison eat grass, moving constantly and continuously as they eat so that they rarely overgraze an area. It can often be found wallowing in the dirt, ridding itself of the insects that spend their time flying near the bison. They have very few predators, and are threatened mainly by wolves, coyotes, and grizzly bears.

photo M. Noonan

Our group decided that the bison should be included as one of our focal species for this program for several reasons. First, to many people in our immediate area (Buffalo, NY), the bison is a common image. It is often used as a logo for sports teams, like the Buffalo Sabres, the Buffalo Bills and the Buffalo Bisons. But, even so, many people living in Buffalo have no idea what bison are really like and are unaware of their status in the wild. Second, the bison can be thought of as a flagship species of American conservation, having been brought back from the brink of extinction during the past century.

American Bison Taxonomy/Description

Bison belong to the Mammalian Order Artiodactyla, in the family Bovidae. Bovidae also includes goats, sheep, cattle, and antelope. The bison's scientific name is Bison bison, which is simply Latin for "bison".

Bison have broad heads with horns, humped shoulders, and thin limbs. Their fur is long and dark; bulls have "beards". Male bison (or bulls) grow to about 6ft in height and weigh 2,000 pounds! Female bison (or cows) average about 5.5 feet in height and weigh 1,400 pounds. Bison can run up to 38 miles per hour. Bison live 12-15 years in the wild.

American Bison Habitat/Diet

The American Bison lives on mixed grasslands/prairie in western North America.

Bison are ruminants. They have a four-chambered stomach, which allows for the digestion of cellulose and the ability to "eat and run". As grazers, they feed on succulent grasses, sedges, and rushes. They will also eat forbs. Bison eat five times daily (before dawn, before midday, mid-afternoon, before sunset, and at about midnight). Herds practice "wave feeding" – a few members of the group will start grazing before being followed shortly thereafter by the rest of the group. An older cow will lead the group in a given direction; when she slows, the rest slow and resume feeding. Bison usually drink water once daily. They eat snow in winter. Essential minerals are obtained from mineral licks.

photo M. Noonan

American Bison Behavior/Reproduction

Bison are dangerous mammals and should be observed in the wild at a distance of at least 100 yards. Any closer might provoke a nasty defensive reaction. Alarm postures include both a raised head and an arched tail, which may be accompanied by defecation. If you see these signs, back off! Grunting, snorting, sneezing, and roaring are forms of vocal communication.

photo M. Noonan

Bison often do what behavioral biologist call "loafing". They lie on their bellies or sides, or stand with their heads drooping and eyes closed. Often, bison in such loafing postures are digesting their food.


Bison "wallow". This means they roll on the ground from side to side. This is a grooming activity which aids in the removal of parasites from the fur. Wallowing also allows male bison to lay down their scents and to displace aggression. Bison will also rub themselves on saplings or roadside posts. This is a way of removing the heavy winter coat in spring.

photo M. Noonan

When not in the breeding season, bison travel in separate groups of females with their young and males that are of reproductive age. In the summer, the rut begins. You can hear the bulls roar more and more frequently in late July and early August. Then, the bulls join the cow-calf groups and begin to court – or "tend" – females with lip curling and sniffing. The males each keep their prospective mates from mating with other males; sometimes resorting to combat if need be. Mating occurs if a female is receptive, and then the pair bond breaks hours later. In the middle of May of the following year, calves are born following nine-and-a-half months of gestation. Single calves are born buff-colored and precocial. "Playgroups" (cows and calves) are formed in early summer. Young bison often play, engaging in mock battles with one another.

photo M. Noonan

American Bison History/Folklore

Before the arrival of Europeans to the New World in the 15th century, 50 million bison populated the vast plains of western America, and could be found scattered throughout the whole of the continent. They could be found grazing from the Atlantic Ocean almost to the Pacific and from Mexico and Florida into Canada. This animal was essential to most or all Native Americans. They would kill bison and use it for food, clothing, shelter, etc. This, however, had little impact on the number of bison living in North America. It was during the time period beginning in the 1830’s that hunting for hides became the major cause of the reduction of the bison population. U.S. government policy supported the bison’s execution in order to control hostile Indian tribes through starvation, associating bison carcasses with “discouraged Indians”. The animal was on the brink of destruction, with fewer than 1,000 individuals remaining. Due to this large decrease in numbers, a plan to rescue the bison was formed to ensure the species did not go extinct. In the present, and because of exceptional game management, the North American population exceeds 200,000 that are spread throughout the west. However, there are only approximately 16,000 animals that can be considered free-roaming in the wild.

photo M. Noonan

The American Bison evolved from a species of large grass-eater that migrated to North America from Siberia 40,000 years ago. Before European settlement of the Great Plains, approximately 60 million bison existed in North America. The population plummeted to 1,100 as European settlers killed nearly every bison. Bison were shot for their valuable hides and for their meat which was a hot commodity for railroad workers. Railroads companies also encouraged "adventure" hunts where tourists would shoot bison from the train for sport. (Some suggest that this was actually part of an attempt to subdue the Plains Indians, who depended on the bison for food.)

photo M. Noonan

The Oglala Sioux Indians have a legend of the White Buffalo Woman. She was encountered by two hunters and presented to their chief a pipe that had carved into it a bison calf. It reminded the people of their connection to all living things.

Our Experiences with American Bison

While studying in the Badlands National Park and the Buffalo Gap National Grassland, we had some very interesting encounters with Bison. We studied many signs of the bison's presence in the prairie (discarded fur, deep wallows, "buffalo chips", and many, many tracks). On most days, we also got to directly observe the animals themselves -- sometimes more closely than we would have preferred. On one day, as we hiked through the Badlands National Park, a herd of 40 bulls appeared before us. Noticing that their tails were standing on end, we realized that these Bison were not as happy to see us as we were to see them. The whole herd then actually started to move toward us as a fast walk. Having to act quickly, Dr. Noonan backed our group up to a gully area where we were able to out-maneuver the bison and disappear from their line of sight. Luckily, we all escaped untouched by 80 tons of Bison! Thinking that we were free from danger, we continued our hike through the park. Then another pair of bison began to follow us. We felt like we were being stalked!

American Bison Conservation

"What is man without the Bison? If all the beasts were gone, men would die from great loneliness of spirit. For whatever happens to the beasts also happens to the man".

photo M. Noonan

Once pushed to near extinction

Approximately 60 million Bison roamed North America when Europeans discovered it. When settlers moved west, the bison were pushed to near extinction. During the 1800s, the railroad brought hunters who killed the Bison for sport. Bison were also killed for their hides and meat. The United States army in the mid 1800s began to kill the Bison to take away the Native Americans’ food source. Increased farming in the west brought domestic animals and diseases against which the Bison had no defense. By 1889, fewer than 1,100 Bison remained in the United States and Canada.

Brought back from the brink

Luckily, during the destruction of the wild bison herds, some people protected small herds of captive animals on private land. These animals were subsequently used to repopulate some North American parks with these magnificent animals. The first bill to save the Bison was introduced in Congress in 1874. In 1905, the American Buffalo Society was formed with Teddy Roosevelt as Chairman. Today there are approximately 200,000 Bison in North America, although most of them are still found only in managed or ranched herds. (Bison are ranched for their meat in all 50 states and in all Canadian provinces.)

photo M. Noonan



Artiodactyla – Mammalian Order meaning "even toed", which consists of all even-toed hoofed mammals, including families that contain cattle, antelope, deer, camels, and hippopotamuses

grazer - feeds on grass or herbage

precocial - relatively mature and mobile from the moment of birth

ruminant - any hoofed animal that digests its food in two steps, first by ingesting the raw material, such as grass or leaves, then regurgitating it in partially digested form, called the cud, which is then also eaten

Content provided by Canisius College students under the direction of Michael Noonan, PhD.