Bison

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Single buffalo standing in front of a service road sign amid green prairie grasses
Bison frequently make use of park infrastructure as scratching posts

NPS Photo / Larry McAfee

Names and lifeways

What’s in a name?

There are many names for the American Bison. Scientifically, the plains bison subspecies found in Badlands National Park are of the genus Bison, of the species bison, and the subspecies bison. If you ask a wildlife biologist, these animals are called Bison bison bison!

Although these animals have “bison” three times in their scientific name, they are often called buffalo. The word buffalo is derived from the French “bœuf,” a name given to bison when French fur trappers working in the US in the early 1600s saw the animals. The word bœuf came from what the French knew as true buffalo, animals living in Africa and Asia. Although this name was a mix-up of two different animals, many people still know bison as buffalo today.

Another name for these animals is “tatanka.” Tatanka is the Lakota word for bison. Bison are incredibly important in Lakota culture; the Lakota are traditionally nomadic and would have spent their lives following bison before Euro-Americans settled the West. Another word for bison in Lakota is “pte.” The Lakota are sometimes known as pte oyate, meaning “buffalo nation.”

How many bison have lived in the US?

Bison were once abundant in the American landscape. Their natural range extended from Canada to Mexico and from New York to Oregon. Scientists and historians estimate that there were at least 30 million bison roaming the country before Euro-American settlement of the West.

Before Euro-American expansion into the West, these millions of bison were a major part of life in Lakota culture. The Lakota people lived as nomads, following herds of bison and hunting them when necessary. Different parts of a bison supplied everything the Lakota needed – food, clothes, blankets, knives, fuel – and every part of the animal was put to use once it had been killed. Bison also played (and continue to play) an important spiritual role in Lakota life, appearing in many oral histories and spiritual narratives.

When settlers expanded into the American West, these animals nearly disappeared. Major hunting of bison began in 1800 and increased with time as legislation like the Dawes Act and Homesteading Acts passed. While the Lakota utilized every part of the animal, this systematic hunting resulted in a lot of waste – Euro-Americans used only hides, which could be sold as robes or rugs, and tongues, which could be sold as a delicacy. Although this hunting was for often for sport, there was a secondary motive: the US government wanted to disrupt and disband Native American ways of life, and one way to do that was to kill off bison, which were central to the culture and well-being of many plains tribes.

Plummeting from a previous population of 30 million, there were an estimated 325 wild bison left in the country by 1884. Luckily, a few conservationists had the foresight to protect the last of this species, and their efforts in the late 19th century are the reason why about 20,000 bison now roam public lands.

buffalo grazing on a sunny day with patchy fur
Bison grow thick coats to get through the winter which they shed in preparation for summer

NPS Photo / Troy Hunt

Bison Behaviors

A Day in the Life

Bison are enormous animals – they can get up to 6.5 feet tall and weigh up to 2,000 pounds. Their incredible weight makes them the heaviest land mammal in North America! Despite their weight, bison are remarkably agile. They can run up to 35 mph and have a vertical leap of six feet.

Being such a huge animal means eating a huge amount of food. Bison are grazers and spend from 9-11 hours every day ingesting up to 1.6% of their body mass in forage. Being a ruminant (an animal that chews their cud and has a complex digestive system), bison can get nutrition from hard, dry forage where other animals cannot. While grazing, bison roam an average of 2 miles every day.

A Year in the Life

Many people ask where Badlands bison migrate for the winter – and the answer is that they stay right here! Bison are incredibly well-adapted to the cold. They develop a thick winter coat to keep them plenty warm. Their winter coats are so thick that snow sits on top of them and never touches the bison’s skin. They even use their enormous heads, with the help of their supportive neck humps, to plow snow out of their way while grazing. Sometimes bison almost seem impervious to cold – unlike most animals, which turn their backs to the wind, bison face oncoming winter storms.

In the spring, bison lose their winter coats, often “wallowing” to loosen winter fur. Wallowing is a behavior in which bison roll around on the ground and cover themselves in mud and dirt. This behavior has many benefits for bison – it helps them to rid of their winter coats, protects them from bug bites, and spreads their scent for mating. Wallowing is also beneficial for prairie ecosystems! It compacts and churns up soil, making way for new plants. The depressions left behind by bison, known as wallows, can also serve as small water reservoirs. These little ponds benefit other thirsty animals and provide a home for more water-reliant prairie vegetation.

Bison breed in the summer. Male bison compete for mating rights, butting heads with other bulls. In these competitions, male bison may also lower their heads, paw at the ground, and emit a bellow which can be heard up to three miles away. A bison’s gestation period is 9.5 months – similar to a human’s! When babies are born in the spring, they are called “red dogs” for their resemblance to reddish canine companions.

Single buffalo walking through a vast badlands landscape under a blue sky
The preservation of prairies has given the buffalo a place to recover and flourish

NPS Photo / Carl Johnson

Bison in the Badlands

While Badlands National Park is well within the historic native range of bison, they had to be reintroduced after the species suffered devastating losses in the late 19th century. Bison were returned to the Badlands in 1963, with a source herd transferred from Theodore Roosevelt National Park. The Badlands herd now consists of around 1,200 bison.

The Badlands bison roundup occurs each fall. During the roundup, rangers collect as many bison from our herd as they can in our corrals. Once in the corrals, rangers collect biological data from each bison and tag recently born bison. Sick and injured bison also receive treatment at this time. After all the information has been collected, we divide the bison the park will keep from the ones it will not. The bison that the park does not keep will go to live on other public lands or will be given to groups like the Intertribal Buffalo Council, which is a coalition of Native American tribes dedicated to preserving traditional buffalo practices.

We encourage you to keep an eye out for bison on your trip through the Badlands, but please remember that they are wild animals. Maintain a distance of 100 feet whenever possible and do not provoke bison. These animals can cause severe injuries or even deaths if angered.

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    Last updated: July 28, 2020