The U.S. Fish and Wildlife Service said Thursday the review will settle a lawsuit by environmental groups that challenged a 2008 decision saying there wasn't enough information to decide that the animal needed federal protection.

The wolverine's current range includes California, Colorado, Idaho, Montana, Oregon, Washington and Wyoming.

The weasel-like animals, bigger than badgers and known for their ferocity, were once common in the northern Rockies. But they were nearly wiped out by 1930 due to trapping and poisoning by farmers and ranchers.

Colorado documented its first wild wolverine in 90 years when one roamed from northwest Wyoming into the state last summer.

California's Sierra Nevada, where it's believed wolverines have been extinct since as early as the 1920s, has been visited the past three years by a wandering wolverine.

Fish and Wildlife Service spokeswoman Diane Katzenberger said it's unclear how many wolverines there are. That is one of the questions the review will try to answer, she said.

The agency is seeking information about wolverines from other government agencies and the public, including industry and conservation groups, until May 17. The finding is expected by the end of the year.

Paige Bonaker, staff biologist with the Denver-based Center

for Native Ecosystems, said wolverines deserve to be studied because their numbers have dropped. She said there's no good estimate of the number of wolverines in the West, but added the animal is gone from areas, including Colorado, where trapping records show they once existed.

"And they have threats coming from all sides: climate change, habitat fragmentation," Bonaker said.

The agency said Thursday it will also launch a yearlong study of whether the Northern Rockies fisher, another member of the weasel family, should be protected.