Bison: Can't Leave Park, Can't Escape Slaughter

Record number of bison slaughtered around Yellowstone National Park

(04/02/2008) - WASHINGTON, D.C – A record number of bison – over 1,100 – have been slaughtered this winter around Yellowstone National Park. The removal of nearly one-quarter of the park’s bison population dramatically demonstrates the need to reform the rules governing the last stronghold for America’s wild bison.

“Yellowstone’s bison are America’s bison, the last pure descendants of the tens of millions of bison that once thundered through the American landscape,” said Jamie Rappaport Clark, executive vice president of Defenders of Wildlife and former director of the U.S. Fish and Wildlife Service under the Clinton administration. “Yet as soon as they set foot outside of Yellowstone Park, even onto publicly owned national forests, they are harassed and killed. This is truly one of the worst examples of wildlife management in the country.”

The recovery story of bison is both courageous and historic. Once numbering in the tens of millions, America’s vast herds of bison were almost wiped out in the 1800s. A remnant herd of a couple dozen bison made a last stand in Yellowstone Park, where they staged a comeback against all odds - only to be turned upon by the authorities responsible for their protection. Goaded by the livestock industry, the Montana Department of Livestock is responsible for indiscriminately slaughtering bison that venture outside the park in winter looking for food – with help from Yellowstone park rangers.

“Yellowstone Park is being treated like a zoo,” said Mike Leahy, director of Defenders of Wildlife’s Rocky Mountain Region. “Bison aren’t allowed outside the park’s borders, and those that leave the park in search of food are either chased back in or shot.”

Despite the wealth of public lands around Yellowstone Park that historically supported bison herds, bison are restricted to the park itself. When Yellowstone’s bison population exceeds an arbitrary population cap, federal and state agencies including the National Park Service undertake a massive cull to reduce the population.

“There’s plenty of room for bison on public lands around the park such as the Gallatin National Forest in Montana,” said Leahy. “The only reason we don’t have bison there now is that the livestock industry is calling all the shots and demanding that bison be kept out of this historic habitat.”

Faulty science and biased politics have led to regular winter roundups of bison that venture outside Yellowstone Park. They are killed by and at the request of the Montana Division of Livestock, due to an unfounded fear that they might transmit a disease called brucellosis to cattle grazing on public lands. Yet there has never been a documented case of a bison transmitting brucellosis to cattle in the wild.

This year, the vast majority of bison exterminated for this reason were not even tested for brucellosis before being put to death.

“Ironically, Montana continues to attract tourists to the state and the park by marketing alluring images of bison roaming free in the wild as they did in days gone by,” said Leahy. “The truth is that these bison are by no means free. If they set foot outside the ‘Yellowstone Zoo’ they will be killed.”

Montana’s new Tourism and Recreation Strategic Plan, “A Fresh Path Forward,” recognizes the value of Montana’s wildlife to visitors from around the world.  However, Montana does not. 


Bison once roamed across much of North America. Today bison are ecologically extinct throughout most of their historic range, except for a few national parks and other small wildlife areas. Yellowstone National Park has the largest population of free-roaming plains bison (down to 3,000 from 4,700 at the beginning of winter), and the only herd to have remained on the landscape continuously

Historically, bison numbered an estimated 20-30 million. Unregulated shooting of bison, which culminated in mass slaughters during the 1870s, reduced the population to in the hundreds by the late 1800s. Today, a few hundred thousand bison live across North America. Most are not pure bison but rather have been cross-bred with cattle in the past and are raised as livestock on ranches. Fewer than 30,000 bison are in conservation herds.


Defenders of Wildlife is dedicated to the protection of all native animals and plants in their natural communities.  With more than 1 million members and activists, Defenders of Wildlife is a leading advocate for innovative solutions to safeguard our wildlife heritage for generations to come.  For more information, visit



Mike Leahy, (406)586-3970
Erin McCallum, (202)772-3217