Plains bison
Bison bison bison

The Plains bison (Bison bison bison ) is one of two subspecies/ecotypes of the American bison, the other being the wood bison (B. b. athabascae ). A natural population of Plains bison survives in Yellowstone National Park (the Yellowstone Park bison herd consisting of an estimated 4,800 bison) and multiple smaller reintroduced herds of bison in many places in the United States as well as southern portions of the Canadian Prairies.


The color of the American bison fur varies in the front and back of its body and is different shades of brown. Bison is hunchbacked and it has a long beard on its chin. The forehead is wide and narrow while the neck is short. Hind legs are smaller than front legs, making up a scarp from humpback to tail. Length of hair differs in front and rear, especially in males: front hair is significantly longer than rear hair. Horns of bison are black, bent inward withal upward, and pointed. Male bison are significantly larger and heavier than females. Plains bison are often in the smaller range of sizes, and wood bison in the larger range. Head-rump lengths at maximum up to 3.5 m (11 ft 6 in) for males and 2.85 m (9 ft 4 in) for females long and the tail adding 30 to 95 cm (1 ft 0 in to 3 ft 1 in). Heights at withers in the species can reach up to 186 to 201 cm (6 ft 1 in to 6 ft 7 in). The heaviest wild bull for Plain bison ever recorded weighed 1,270 kg (2,800 lb) while there had been bulls estimated to be 1,400 kg (3,000 lb).




Introduced Countries
Biogeographical realms

In the past, a huge number of bison thundered North America from Mexico to Alaska. Then, mass killings of these impressive animals led to their total extermination from the main area of their habitat. However, bison survived and currently they live primarily in Canada and the western part of the USA, usually in protected areas and national parks. American bison prefer to inhabit river valleys, prairies, and plains. Typical habitat is open or semiopen grasslands, as well as sagebrush, semiarid lands, and scrublands. Bison also graze in hilly or mountainous areas where the slopes are not steep.

Plains bison habitat map


Climate zones

Plains bison habitat map
Plains bison
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Habits and Lifestyle

American bison is diurnal, being active all day long. They are usually relatively passive during the day, becoming particularly active at dusk and dawn. They spend a lot of time cleaning the fur or grooming: they rub their head, sides, and necks against trunks of trees. Bison are able to be constantly on the move, passing long distances as long as there is food. Cows, female bison, are leaders of family groups while males stay separate, creating small groups or living solitarily. As the mating season comes, males join female groups. Bison like rolling, weltering, and rubbing against the ground. Wallows are recesses - dust bowls with no vegetation, having circular form, formed as a result of bison’s wallowing on the ground.

Seasonal behavior

Diet and Nutrition

Bison are herbivores (graminivores) and, more specifically, grazers, chewing grass all year round. However, in absence of grass, they eat other greenery found in the area such as sagebrush. The presence of water is another important component of their life: they can’t last long without a source of water.

Mating Habits

285 days
1 calf
1 year

Bison are polygynous, meaning that a dominant male, or a bull, mates with a group of females. The season for breeding takes place in summer, from June to September while the gestation period lasts about 285 days. A female can give birth to a single calf each season. Newborn calf weight about 15-25 kg. To give birth, bison females choose shelter, a distant place far from the herd. Protection of the calf lies on the shoulders of females whereas males don’t take part in this process. Babies are breastfed for 7-8 months and weaned when they are one year old. Males reach sexual maturity at the age of 3 years and females - from 2 to 3 years.


Population threats

The most notable threats to the population of this species as a whole are long-time persecution of bison from their habitat; slow growth of population in closed and protected areas; genetic manipulation for commercial purposes; hybridization and backcrossing of bison and other cattle as well as between different bison subspecies; natural limiting factors in conditions of reservations; and the possible threat of depopulations of bison because of its wild populations’ carrying cattle deceases; continuous culling of bison in order to preclude brucellosis and bovine tuberculosis infection.

Population number

According to the IUCN Red List resource, the total population size of the American bison is around 31,000 individuals in 68 conservation herds in North America. The total wild population of the species is estimated to be between 11,248 and 13,123 mature individuals in North America. Currently, the American bison is classified as Near Threatened (NT) on the IUCN Red List but its numbers today are stable.

Ecological niche

Bison was an important component of the flatlands ecosystem in its habitat. When grazing, the animal thrusts its hooves into the soil, thus fertilizing it. Plains, grazed by bison, were inhabited by prairie dogs, protecting them against predators due to being shorter and thus providing a better view of the surrounding area. Corpses of bison were a delicacy for scavengers while their meat was the main source of food for the local population of wolves and humans. Bison fertilized the plains of the habitat thus becoming predecessors of farmers.


At one time, at least 25 million American bison were spread across the United States and Canada. However, by the late 1880s, the total number of bison in the United States had been reduced to fewer than 600. Most of these were collected onto various private ranches, and the last known free-roaming population of bison consisted of less than 30 in the area which later became Yellowstone National Park. Although farmers and ranchers considered bison to be a nuisance, some people were concerned about the demise of this North American icon, so individual landowners and zoos took steps to protect them. Some people saved bison with the express purpose of ranching or hunting them (see Antelope Island bison herd). Others such as the American Bison Society were also formed with the idea of saving the species and reintroducing them to natural range. Plains bison have since been reintroduced into a number of locations in North America. Five main foundation herds of American bison supplied animals intended to save them from extinction. The northernmost introduction occurred in 1928 when the Alaska Game Commission brought bison to the area of present-day Delta Junction. Bison taken from this transplant were also introduced to other Alaska locations, including Farewell and Chitina. The Delta Junction herd prospered the most, with a population of several hundred throughout the late 20th century. This herd is popular with hunters interested in hundreds of pounds of high-quality meat, but has been a problem for farming operations in the area. Though American bison generally prefer grasslands and plains habitats, they are quite adaptable and live in conditions ranging from desert, as in the case of the Henry Mountains bison herd, to forested areas, such as those of the Yellowstone Park bison herd; yet, they are all of the same subspecies Bison bison bison. Currently, over 500,000 bison are spread over the United States and Canada. However, most of these are on private ranches, and some of them have small amounts of hybridized cattle genes. Significant public bison herds that do not appear to have hybridized domestic cattle genes are the Yellowstone Park, the Henry Mountains, the Custer State Park, the Wind Cave, and the Wood Buffalo National Park bison herds and subsidiary herds descended from it in Canada.

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Park officials transferred Plains bison from Fort Niobrara National Wildlife Refuge to Theodore Roosevelt National Park's South Unit in 1956 and its North Unit in 1962 for population increase.

In 1969, Plains bison from Elk Island National Park were released into Prince Albert National Park in Saskatchewan, creating the Sturgeon River bison herd. At a population around 300 animals, they form a free herd able to wander where they please. The bison are spread throughout Prince Albert National Park's southwestern corner, as well as some crown and private land in the area.In 2006, Plains bison from Elk Island National Park in Alberta were released into Saskatchewan's Grasslands National Park. This marks the first time Plains bison have wandered the shortgrass prairies of Canada since their near-extinction at the turn of the 20th century. According to the national agency Parks Canada, the entire breeding population of these wild and "semiwild" bison are the descendants of just eight individuals that survived the period of near-extinction, due to overhunting and tuberculosis infecting the herd.

A herd of about 650 of these animals lives in, and can be seen at, the Wichita Mountains Wildlife Refuge near Lawton, Oklahoma. The herd was started in 1907 with stock from the New York Zoological Park, now known as the Bronx Zoo and located in the Bronx Park. Fifteen animals were shipped to Oklahoma, where bison had already become extinct due to excessive hunting and overharvesting by non-native commercial buffalo hunters from 1874 to 1878. Some of these specimens have been released in other areas of the United States, such as Paynes Prairie in Florida.

Only one Southern Plains bison herd was established in Texas. A remnant of the last of this relict herd had been saved in 1876. "Molly" Goodnight had encouraged her rancher husband, Charles Goodnight, to save some of the last bison which were taking refuge in the Texas Panhandle. By saving these few Plains bison, she was able to establish a buffalo herd near the Palo Duro Canyon. This herd peaked at 250 in 1933. Bison of this herd were introduced into the Yellowstone National Park in 1902 and into the larger zoos and ranches throughout the nation. A herd of around 80 of these animals lives in the Caprock Canyons State Park near Quitaque, Texas, located about 50 miles northeast of Plainview, Texas.

Ted Turner owns America's largest secured bison herd in Cimarron, New Mexico's Vermejo Park Ranch. Boy Scouts of America own a private bison herd in Cimarron's Philmont Scout Ranch.

In 2013, bison were reintroduced to Fort Belknap Indian Reservation from Yellowstone National Park.

A herd of Plains bison were successfully reintroduced to Banff National Park in Alberta in early 2017. The bison were kept under observation in an enclosed pasture of the park until the summer of 2018, after which they have been allowed to roam free. Observation is to be continued until 2022 according to Parks Canada.

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Fun Facts for Kids

  • Dense coat of bison protects it from the rough elements of the American plains. In winter the coat becomes solid and even thicker, so that bison are seen with snow on their backs, not melting due to their coats isolating their warm skin from the outer surface.
  • The groups that bison create are called obstinacies, gangs, or herds.
  • Hunch on its back is nothing but a bunch of muscles. The hunch also helps bison to move into the snowpack.
  • Bison is an excellent jumper, able to jump up to 6 feet off the ground.
  • Bison have a heightened sense of hearing, being able to identify big objects from a 1 km distance and moving objects - at a distance of 2 km.
  • Along with jumping, bison are excellent at running and swimming.
  • Newborn calves start walking and running a few hours after being born.

Coloring Pages


1. Plains bison Wikipedia article -

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