Wolverines are not established residents in Colorado. This large, solitary member of the weasel family requires expansive, cold, high-altitude territory. While Colorado contains some of the best potential habitat in the contiguous United States, no permanent, breeding population exists within the state’s borders today. Any wolverines currently found in Colorado are extremely rare, transient visitors dispersing from northern populations.
Historical Presence and Extirpation
Wolverines were once native to the Rocky Mountains, with their range extending as far south as Colorado. Historical records confirm their presence in the state during the 19th and early 20th centuries, though they were likely never common. The last confirmed record of a wolverine in Colorado dates back to 1919.
The primary causes for the species’ disappearance, known as extirpation, were widespread unregulated trapping and poisoning. Early settlers and resource extraction operations viewed the wolverine as a pest or competitor. These aggressive predator control campaigns effectively eliminated the wolverine from Colorado by the early 1900s.
Current Status: Documented Transient Individuals
Despite the lack of an established population, Colorado has confirmed evidence of wolverines in recent decades. These records involve transient male individuals that have dispersed vast distances from established northern populations. Male wolverines have massive territories and frequently undertake long-distance movements in search of mates or new habitat.
The most notable confirmed sighting occurred in 2009, when researchers tracked a male wolverine, designated M56, traveling into north-central Colorado. This animal was radio-collared near Grand Teton National Park in Wyoming and traveled over 500 miles, marking the first confirmed presence in the state in 90 years. M56 remained in Colorado for nearly a year, spending time near Rocky Mountain National Park and Leadville before moving north again.
M56 was a dispersing animal, not the start of a breeding group, which requires both males and females to establish territories. Colorado Parks and Wildlife currently lists the wolverine as “state endangered.” This designation acknowledges the species’ historical presence and the continued possibility of transient migrants.
Ecological Constraints of Colorado’s High Country
Wolverines struggle to establish a permanent, reproductive population in Colorado due to their unique reproductive requirements. Female wolverines must den in areas with deep, persistent snowpack that lasts until mid-May. This snow is necessary to protect their kits from predators and insulate them from freezing temperatures.
The availability of specific denning habitat is the primary ecological constraint in the southern Rocky Mountains. Climate change presents a growing challenge, as warming temperatures threaten the persistence of deep spring snowpack, particularly at lower elevations. However, high-resolution snow modeling suggests that Colorado’s highest elevations are predicted to retain adequate snowpack to support denning through the mid-21st century, making the state a potential “climate change refugium.”
Policy and Potential Reintroduction Efforts
The North American wolverine was federally listed as a threatened species under the Endangered Species Act in late 2023. This listing provides a legal framework for conservation. Colorado lawmakers passed Senate Bill 24-171 in 2024, which authorizes Colorado Parks and Wildlife (CPW) to begin the process of wolverine reintroduction.
The reintroduction effort depends on federal approval to designate the population as a nonessential experimental population under a Section 10(j) rule. This designation allows CPW greater flexibility in managing the species and addresses potential conflicts, such as compensating landowners for livestock losses. The state plans to release approximately 45 wolverines, consisting of 30 females and 15 males, over a three-year period once federal permits are secured.