A federal judge ruled Wednesday in a case argued by Friends of Animals that the U.S. Fish and Wildlife Service illegally denied Endangered Species Act protections for the Yellowstone National Park bison population. The ruling overturns the U.S. Fish and Wildlife Service’s negative 90-day finding that concluded there was not substantial information supporting the need to protect the bison, which in 2016 were officially designated as the national mammal, under the Endangered Species Act.

State and federal agencies have been killing bison in and around Yellowstone National Park in an effort to reduce the imperiled population and to cater to unfounded fears of transmission risk to local livestock operations of brucellosis, a non-native disease brought to the region by livestock. However, a recent study by the National Academy of Sciences found that of all the instances of brucellosis transmission from wildlife to domestic cattle, not one single incident was attributable to bison. Only about 5,000 bison remain in the Yellowstone herds, which constitute the only wild, genetically pure bison to continuously occupy their native range in the United States.

“This is huge that the Court recognized the importance of science,” says Michael Harris, an attorney with Friends of Animals who argued the case for Buffalo Field Campaign and Western Watersheds Project. “It sends a signal to the Fish and Wildlife Service that they cannot manipulate the science to serve political interests, like cattle ranchers.”

The court ruled that the U.S Fish and Wildlife Service improperly ignored an important scientific study that concluded there are two separate and genetically distinct herds of bison – the Central Interior herd and the Northern herd – in Yellowstone National Park. The current plan treats bison as a single herd, failing to provide safeguards to maintain both herds as distinct and isolated units. Currently, the Central Interior herd may already be too small to maintain its viability from a genetic standpoint.

“This moves bison back into queue for full and fair consideration under the Endangered Species Act,” said Buffalo Field Campaign Executive Director Ken Cole. “That’s so important for these small subpopulations who are at grave risk of blinking out under current management.”

Millions of bison once roamed North America but were driven to near extinction by the late 1800s and hundreds were captured and sent to zoos and private ranches, court documents note. The just under 5,000 that are left occupy an area in and around Yellowstone. The bison population is managed by an interagency plan that allows for the capture or slaughter of bison leaving Yellowstone and the hazing of herds via helicopters to drive them back into the park. Every winter and spring, hunger pushes the bison to lower elevations across the park boundary in Montana and when they cross over into the state, they can be captured, quarantined or slaughtered if the National Parks Service census finds their population has exceeded the 3,000. A combination of hunters and Wildlife Service agents shoot the bison.

Several petitions have been filed in recent years to list the bison as endangered or threatened species because of loss due to livestock grazing, development, hunting, climate change and disease and because the management plan is inadequate to ensure the survival of the species.

In his ruling, U.S. District Court Judge Christopher Cooper noted that where there is disagreement among reasonable scientists, the FWS should make a “may be warranted” finding regarding a petition for ESA status. And that the service in not granting that “simply picked a side in an ongoing debate in the scientific community which is improper” at this point.

“The Fish and Wildlife Service made a political decision to suppress and ignore science in order to deny the Yellowstone bison the protection they deserve,” said Josh Osher, Montana director for Western Watersheds Project. “The administration is clearly bowing to the influence of the livestock industry and its agenda to minimize bison populations and their natural migrations, despite their status as the national mammal.”

Since 2016, more than 1,400 Yellowstone bison have been killed, according to Buffalo Field Campaign. More than 10,000 have been killed in the past 30 years.

Friends of Animals President Priscilla Feral said that continued slaughter of the bison only benefits trophy hunters and agencies who make money from hunting permits. Montana charges $10 to apply for bison hunting permit and $125 for the license itself.

“Because of cattle ranchers’ irrational fear of a trumped up brucellosis scare, hunting interests get to kill our national mammal and put them at risk of extinction while the state of Montana reaps revenues from hunting permits,” said Feral.

For more information on Friends of Animals’ efforts to save the bison, click here.