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Colorado Governor Jared Polis signed Senate Bill 24-171 into law on May 20, authorizing the Colorado Parks and Wildlife (CPW) to prepare a restoration plan for reintroducing the North American wolverine to a state that advocates say has the largest block of wolverine-ready habitat in the continental U.S., enough to shelter 100 to 180 animals at full carrying capacity.

“I am thrilled to welcome wolverines back to Colorado!” Gov. Polis said during the signing ceremony, held at Loveland Pass in the Rocky Mountains. “A diverse and healthy environment strengthens Colorado’s booming eco-tourism and outdoor recreation sectors. Today, we begin to add wolverines to the list of animals reintroduced to Colorado, ensuring Colorado remains the best state in the nation for eco-diversity and outdoor enthusiasts.” 

Reintroduction Will Take Time

The new law creates a framework for reintroduction, but much work remains before any animals are released in the state. Wolverines were listed as threatened under the Endangered Species Act by U.S. Fish and Wildlife Service in 2023, and as long as they remain on that list “CPW will not reintroduce the species in the state until the effective date of a final rule designating the wolverine in Colorado as a nonessential experimental population,” according to a CPW press release. The state wildlife agency will work with federal land management agencies to coordinate where wolverines may be released, and the law requires CPW to develop a plan for compensating livestock owners for any losses caused by wolverines. Biologists say the risk of wolverine depredation on livestock and large ungulates is expected to be low.

Wolverines were once widespread in North America, ranging throughout Alaska, Canada, and the lower 48 from California through the Midwest and into the Northeast. It’s estimated that fewer than 400 remain in the U.S. They were largely extirpated from Colorado by 1919 (and from the rest of the West by the 1930s) and were added to the state’s endangered species list in 1973. A dozen surveys conducted between 1979 and 1996 detected no confirmed presence of the species in the state. The last confirmed Colorado sighting, in 2009, was a wolverine that traveled down from the Grand Tetons in Wyoming.

Colorado has around 20 percent of the estimated wolverine habitat in the U.S., much of it in high-elevation mountains highly resistant to climate change, but it is largely isolated from existing wolverine habitat, making long-distance migrations unlikely. Distinguished by their compact, powerful build and thick coat, wolverines stand about a foot high on average and stretch 3 feet long; male wolverines can weigh up to 45 pounds. Their scientific name, Gulo gulo luscus, is from the Latin term for “glutton.” They are fierce predators and scavengers, known to eat sheep, caribou, and moose carrion and to prey on small mammals such as porcupines, squirrels, beavers, and rabbits—but they have been observed killing larger animals like caribou and deer.