Fewer than 300 wolverines remain in the Lower 48. Colorado Parks and Wildlife (CPW) has now released the state’s first plan to reintroduce the species. Beginning in 2027, the department will release translocated wolverines to help restore the population and the health of mountain ecosystems.
History of the Wolverine
Wolverines, a member of the weasel family, were once widespread in the Lower 48, in states like California, Minnesota, Oregon, and Colorado, according to the Center for Biological Diversity. They thrive in environments at elevations of 10,000 feet or above, and weigh anywhere from 20 to 35 pounds. They are solitary, territorial creatures.
Since the early 1900s, the population has sharply declined, mostly due to trapping and habitat loss. The last wolverine population in Colorado was recorded in 1919. In 2023, they were added to the Endangered Species List.
In 2024, the Colorado State Legislature approved a measure to reintroduce the animal to the state. It’s been an issue on the table in state politics since 1998.
Why Reintroduce?
Beyond serving to help stabilize the population of an endangered species, reintroducing the wolverine has other benefits. The animal is naturally an opportunistic scavenger-predator. In addition to hunting small mammals like squirrels and rabbits, they’ll eat leftover carcasses of sheep, caribou, and moose that other, larger predators have left behind.
As the nonprofit Defenders of Wildlife explains, “Wolverines play an important role as nature’s cleanup crew. By scavenging dead animals, they help recycle nutrients back into the ecosystem and reduce disease spread by eating carcasses.”
The Plan
According to CPW, over 94% of the planned reintroduction habitat is on federal land. The areas include parts of Rocky Mountain National Park, the Elk and West Elk Mountains, and the San Juan Range. The department will release 15 wolverines per year for 3 years beginning in 2027.
There are no confirmed partnerships yet to source the wolverines, but they’ll likely come from Western Canada or Alaska.
As CPW Wolverine Coordinator Dr. Robert Inman explained in a public meeting of CPW, litter loss among wolverines is quite common, with young surviving only about half the time. Depending on how the species fares, there may need to be more reintroductions.
Wolverines have extremely large home ranges (up to 350 square miles for males) and exist in very low densities, so the state could support a capacity of around 100 animals.
“Restoration here could increase population size in the lower 48 by 30%. That’s a massive improvement and arguably the most significant positive step forward we can currently make for wolverine conservation in the Lower 48,” Inman said.
Challenges
As with any reintroduction of a wild animal, site fidelity — or the animal staying in the new area it’s put in — is a major challenge.
Wolverines also tend to cache large stores of food to survive during the winter and support their litters, but, as transplants, the wolverines put into Colorado wouldn’t have those food stores. The CPW plans to stock prospective dens with food, a major logistical feat.
Gray wolf reintroduction programs have sparked significant backlash from livestock owners, but because wolverines have such low population densities, it’s unlikely that they will pose a significant threat to livestock. In places where wolverines exist, like Montana and Idaho, wolverine predation is extremely rare.
This effort is entirely unprecedented. In a press release, the CPW stated, “There has never been an attempt to reintroduce a population of wolverines, and the effort will require attention to detail, the ability to adapt, and a commitment to success.”
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