Millions of bison once thundered across the Great Plains in the early 1800s. But by the end of the century, those vast herds had been virtually eliminated due to unregulated shooting. Today, wild bison are making a small comeback in places like Yellowstone National Park, but they need more room to roam.

Why They’re Important

Historically, bison played an essential role in shaping the ecology of the Great Plains. They graze heavily on native grasses, allowing other plant and animal species to flourish. Prairie dogs prefer areas grazed by bison where the grass is short so they can keep a lookout for hungry predators. Wolves once relied on bison herds as a major food source. And numerous scavengers feast opportunistically on bison carcasses.

Major Threats

Intolerance is the greatest threat to bison. Though bison are no longer threatened with extinction, there are currently very few places where wild bison are allowed to live as wildlife. Almost all of their historic stomping grounds are off limits, due primarily to opposition from livestock interests. Yellowstone – the one place where wild bison were not completely wiped out – is home to the largest free-roaming bison herd in the United States. But even here bison are not allowed to roam much beyond the park boundary and are kept to fewer than about 3,500 in number. When the herd grows above this level, the “surplus” bison are often shipped to slaughter. For all intents and purposes, bison are still ecologically extinct.

What Defenders Is Doing to Help Bison

Defenders of Wildlife is helping to find more places for bison to roam wild. In Montana, we’re working with Native American tribes to make room for wild bison on tribal lands, and we’re putting pressure on state and federal agencies to relocate “surplus” Yellowstone bison to start herds in new areas rather than slaughter these bison on the edge of Yellowstone.

Defenders has also been working with landowners in Gardiner Basin near the north entrance to Yellowstone to come up with ways to live with bison that wander outside the park. To date, Defenders has chipped in more than $50,000 for fencing and other related project costs to help restore bison to tribal lands and to allow them to wander safely in Gardiner Basin.