A wolf so popular that she was referred to as a rock star by rangers was shot and killed in Wyoming just outside Yellowstone National Park late last week, wildlife officials told the New York Times.

The 6-year-old gray wolf, a tourist favorite known as 832F, was the alpha female of Yellowstone's "highly visible" Lamar Canyon pack, according to the Times. She had been fitted with a GPS collar that allowed researchers to track her movements. According to the newspaper, she was the eighth wolf fitted with the collar to be shot during this year's hunting season.

Last fall, Wyoming removed wolves from its list of endangered species, allowing them to be legally hunted on the Yellowstone Park border for the first time in decades.

On Friday, the Humane Society filed a lawsuit in federal court challenging the decision by the U.S. Fish and Wildlife Service to delist wolves in Wyoming. At least 50 wolves have been killed in the state since Oct. 1, the lawsuit claims. (According to the Times, at least 87 wolves have been shot in Montana this season, and 120 shot or trapped in Idaho.)

"The decision to strip Wyoming wolves of federal protection is biologically reckless and contrary to the requirements of the Endangered Species Act," Jonathan Lovvorn, the Humane Society's lead counsel for animal protection litigation, said in a statement announcing the lawsuit. "Wyoming's regressive wolf management plan is reminiscent of a time when bounties paid by state and federal governments triggered mass killings that nearly exterminated wolves from the lower 48 states."

Ranchers say wolf hunting is necessary to protect livestock. According to National Park Service estimates, there are more than 1,700 wolves living in the Rocky Mountain region—most in Idaho.In Yellowstone alone, according to the park's annual wolf report, there were at least 98 wolves in 10 packs—plus two loners—at the end of 2011. And none was more popular than 832F.

"She is the most famous wolf in the world," Jimmy Jones, a wildlife photographer, told the Times.

According to Daniel Stahler, director of Yellowstone's wolf program, data from 832F showed she rarely traveled outside the park. When she did, it was "only for brief periods."