Bison Management

A nursery group of bison cows and calves makes its way through Lamar Valley. Due to high rates of survival and reproduction, the bison population increases by 10 to 17% every year: ten times faster than the human population grows worldwide.
A nursery group of bison cows and calves makes its way through Lamar Valley. Due to high rates of survival and reproduction, the bison population increases by 10 to 17% every year: ten times faster than the human population grows worldwide.

NPS / Neal Herbert


Success & Controversy

The protection and recovery of bison in Yellowstone is one of the great triumphs of American conservation. In 1902, after years of market hunting and poaching, there were only about two dozen bison left in Yellowstone. Over the next hundred years, park employees worked to bring this species back from the brink of extinction. We succeeded, and now face the challenge of helping to manage a healthy, rapidly growing population of bison that sometimes roams beyond our borders onto private land and land managed by other agencies.


Giving bison room to roam takes transboundary collaboration.
A court-mediated settlement reached in 2000 created the Interagency Bison Management Plan (IBMP), which established a cooperative effort to manage bison in and around Yellowstone. Eight groups, including state and federal agencies and American Indian tribes, play a role in making decisions about Yellowstone bison. While there is overwhelming national support for restoring bison, that sentiment is not pervasive in areas where people may have to live with them. To gain support for bison outside the boundaries of Yellowstone, managers must work together to address people's concerns while also conserving the population. The IBMP partners are actively addressing issues related to controlling numbers, hunting, and new conservation areas outside the park.

Yellowstone’s bison population is growing.
Due to high rates of survival and reproduction, the bison population is currently increasing by 10% to 17% per year. Predation by wolves and bears has little effect on bison numbers. More bison migrate out of the park as the population grows. The IBMP partners agreed to stabilize the population around 4,900 animals since 2013 by hunting outside the park and capturing animals near the park boundary. For 2021, the IBMP partners agreed to reduce the population by 500 to 700 animals.

We're working to expand the Bison Conservation Transfer Program.
Bison that are captured are transferred to American Indian tribes for slaughter and distribution of meat and hides to their members. However, many people are uncomfortable with the practice of capturing bison and shipping them to slaughter to reduce numbers. The NPS recently initiated the Bison Conservation Transfer Program with the State of Montana, APHIS, and Fort Peck Tribes. The program identifies bison that don't have brucellosis and transfers them to new areas as an alternative to sending them to slaughter. Since 2019, 154 bison have been transferred to the Fort Peck Tribes. Of those, 82 were transferred to 17 other tribes across the country. Another 110 animals are in the program right now and will be transferred to the Fort Peck Tribes in the coming years.

Many people want hunting to become the primary way to manage bison population numbers.
The State of Montana and several American Indian tribes separately administer bison hunts outside the park. Hunters harvest 200-400 animals during most winters, which still means that some animals must be captured to control numbers. While hunting reduces the number of animals sent to slaughter, it raises other concerns about human safety and inhibiting migration out of the park. All managers are working together to explore ways to improve the safety and quality of bison hunting.

Hunting inside the park is not an option.
Hunting is prohibited in Yellowstone, which is why the park offers some of the best wildlife viewing in the world. A few groups want to open the park to bison hunting, but park managers strongly oppose this idea. Allowing hunting in Yellowstone would affect the behavior of animals and drastically change the experience people expect when they visit. This is not the future we want for Yellowstone, and we don't believe it's the future the public wants either.

Allowing bison in the State of Montana.
For long-term conservation, Yellowstone bison need access to habitat outside the park, similar to other migratory wildlife like elk, deer, and pronghorn. Bison can now roam over more than 75,000 acres adjacent to the park in the State of Montana. Hundreds of bison move into the State on Montana each winter and spring to access critical winter range and calving grounds. These areas also provide for bison hunting opportunities. Thus far, bison have only explored into a small portion of the areas available to them outside the park.

Our Goals

We work to maintain a viable, wild, migratory population of our national mammal.
Yellowstone provides one of the few places where bison live much like their ancestors did: unfenced, and unprotected from harsh winters, drought, or predation. Yellowstone bison also provide a physical link to those ancestors. They were declared our national mammal in 2016 because they’re a symbol of wild America, an important part of our heritage, and a key player in an ecosystem that’s much larger than a national park.

We want to send Yellowstone bison to other conservation areas instead of slaughter.
Yellowstone National Park is building a partnership with Yellowstone Forever and the Greater Yellowstone Coalition to more than double program capacity and lower the number of transfer-eligible animals sent to slaughter from 75% to 35%. These improvements will increase capacity from entering 100 to entering 250 animals into the program over three-year intervals, which increases the number of bison transferred to new areas from 30 to 80 animals per year.

The NPS is initiating a new EIS process to prepare a Bison Management Plan to address NPS management actions within the park boundary that will incorporate new information and changed circumstances since the 2000 plan was approved. A new plan is needed because of new information and changed circumstances since the 2000 IBMP was approved. The following cooperating agencies will provide input during the National Environmental Policy Act (NEPA) process: Confederated Salish and Kootenai Tribes, InterTribal Buffalo Council (ITBC), Nez Perce Tribe, State of Montana- Department of Fish, Wildlife and Parks and Department of Livestock, United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) and Forest Service - Custer Gallatin National Forest. For additional information on the EIS process, the public meetings, and how to provide comments, please visit:

What You Can Do

We encourage you to learn more about bison conservation. Read about the history of bison management, review some questions & answers, download a copy of Yellowstone Bison: Conserving an American Icon in Modern Society, or watch an extended video Q&A with a lead bison biologist.

Get to know all the people and agencies for whom this issue is important, including state legislators, congressional representatives, and the members of the Interagency Bison Management Plan. We’ll need to work together to find a future that includes wild bison.


Last updated: October 20, 2021

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