BILLINGS, Mont. — Animal rights advocates announced a lawsuit against the federal government on Wednesday in a bid to make a Montana mustang population the first group of wild horses to be protected under the Endangered Species Act.
A prior attempt to secure protections for wild horses across the western U.S. as imperiled wildlife failed. But supporters of the idea said they're hopeful to succeed this time by concentrating their efforts on a single population they say is genetically unique.
The Pryor Mountain Wild Horse Range just north of the Wyoming border is home to about 155 mustangs believed to be descended from the mounts of Spanish conquistadors who came to North America in the 1500s.
Attorneys for Friends of Animals argued in the lawsuit that the U.S. Fish and Wildlife Service violated federal law by failing to act on a petition filed last June seeking protections for the animals. The petition was rejected on a technicality because the group submitted it to the federal agency without first notifying Montana officials as was required.
The Connecticut-based advocacy group said that requirement violates federal law. It asked U.S. District Judge Susan Watters to force federal officials to act on the petition within 60 days.
The move comes two years after federal wildlife officials rejected a proposal from the group for protections for tens of thousands of mustangs on federal lands across 10 western states. In that case, officials determined there were no marked behavioral differences between wild horses and their domestic cousins.
Friends of Animals' director of wildlife law, Mike Harris, said the Montana mustangs are more unique. That's largely because the population has long been isolated from other domestic and wild herds in the Pryor Mountains, an arid, rocky range that marks the western boundary of the Great Plains.
"It's able to trace its lineage back to some of the earliest wild horse herds and some of their unique markings and characteristics," he said. "We're going after those herds at most risk."
Fish and Wildlife Service spokesman Steve Segin said there have been no previous cases of horses receiving protections under the 1973 Endangered Species Act. He said the agency was aware of the Montana lawsuit but declined to comment further on it.
The Pryor Mountain horses are subject to periodic roundups to keep their numbers in check, with some of the animals captured by the Bureau of Land Management put up for adoption.
The last such roundup was in 2015, with another planned for this year, bureau spokesman Mark Jacobs said. The bureau manages the Pryor Mountain range in conjunction with the National Park Service and the U.S. Forest Service.
Federal officials have sought for the past decade to reduce the herd's size to prevent overgrazing.
Created in 1968, the Pryor range was the second horse preserve in the nation. It was formed at a time when the capture and slaughter of wild horses for profit faced rising criticism, and culminated three years later in the federal Wild and Free-Roaming Horse and Burro Act.
Wild horses now far exceed U.S. government population goals. Officials say the 60,000 free-roaming on almost 50,000-square miles of land in the West can face starvation.
More than 45,000 wild horses are being held at government corrals and pastures at a cost to taxpayers of $50 million annually.