The wolverine population has dwindled to just 300 in the contiguous U.S.

A coalition of conservation groups has filed a lawsuit against the federal government over its decision to not protect the population of wolverines in the contiguous United States.

The wolverine, a mammal that resembles a small bear with a bushy tail, typically lives in the western mountains throughout Alaska and Canada, according to the U.S. Fish and Wildlife Service, but they have also lived in habitats in the contiguous U.S.

Less than 300 wolverines now remain in the lower 48 states, where they used to roam as far south as New Mexico. Now, small, fragmented populations exist in Idaho, Montana, Washington, Wyoming and northeast Oregon, according to a press release from the Center for Biological Diversity.

The Fish and Wildlife Service’s decision to withhold protection for the wolverine population under the Endangered Species Act will impede the conservation efforts needed to prevent extinction of the species as a result of climate change, habitat fragmentation and lack of genetic diversity, according to the groups’ lawsuit.

The government “has stonewalled” federal protections for the wolverine for decades, said Dave Werntz, the science and conservation director at Conservation Northwest.

A petition to include wolverines under the Endangered Species Act, which protects and recovers imperiled species and the ecosystems on which they depend, was filed in 2000. In 2007, the Fish and Wildlife Service announced it would review the status for the species.

Over the past 20 years since the petition was filed, the Fish and Wildlife Service has been sued five separate times, twice for inaction in decision-making and three times for failing to properly consider science when denying protection under the Environmental Protection Act, said Katie Bilodeau, attorney for Idaho-based conservation group Friends of the Clearwater. In each lawsuit, the court found the agency’s decision unlawful, or the agency chose not to defend its decision, Bilodeau said in a statement.

While the Fish and Wildlife Service did propose to list the wolverine species in the contiguous United States as “threatened” in 2013, the agency withdrew that proposal this October, saying the species does not face an imminent threat due to climate change.

“New research and analysis show that wolverine populations in the American Northwest remain stable,” the Fish and Wildlife Service said in a statement that month.

But the conservation groups say climate change is causing the mountain snowpack that wolverines rely on as their primary habitat to melt away.

“The wolverine is a famously tough creature that doesn’t back down from anything, but even the wolverine can’t overcome climate change by itself,” Amanda Galvan, an attorney for the nonprofit environmental law organization Earthjustice, said in a statement. “To survive, the wolverine needs the protections that only the Endangered Species Act can provide.”

In addition, wolverine populations are at risk from trapping and human disturbance, according to the conservation groups that filed the lawsuit.

The lawsuit filed Monday also accuses the agency of ignoring and failing to utilize the “best available scientific information” in its decision, court documents show. The lawsuit seeks an order for the Fish and Wildlife Service to publish “a new final listing determination” within six months.

The other groups involved in the lawsuit include Defenders of Wildlife, Idaho Conservation League, Jackson Hole Conservation Alliance, Klamath-Siskiyou Wildlands Center, Greater Yellowstone Coalition, Sierra Club and Rocky Mountain Wild.

The USFWS defended its decision in a statement to ABC News.

“We stand by our decision to withdraw the listing proposal,” the statement read. “The best available science shows that the factors affecting wolverine populations are not as significant as believed in 2013 when the U.S. Fish and Wildlife Service proposed to list the wolverine found in the contiguous United States as threatened. New research and analysis show that wolverine populations in the American Northwest remain stable, and individuals are moving across the Canadian border in both directions and returning to former territories. The species, therefore, does not meet the definition of threatened or endangered under the Endangered Species Act.”