Wolverines are powerful and elusive carnivores, often described as resembling small bears. As the largest terrestrial member of the weasel family, Mustelidae, they possess a stocky build and a bushy tail. Adult males typically weigh between 24 and 40 pounds, while females range from 13 and 26 pounds. These animals are recognized for their strength and ferocity, which are considerable for their size.
Where Wolverines Live Today
Wolverines are primarily found in the high-altitude mountain ranges of the contiguous United States. Their established populations reside in Montana, Idaho, Wyoming, and Washington, extending into a small portion of Oregon’s Wallowa Range. While Alaska supports a broader distribution, the focus in the lower 48 states is on these rugged, remote areas of the Northern Rockies and North Cascades.
Individual wolverines have also been documented as transient visitors in states like California’s Sierra Nevada, Colorado, Utah, and Nevada. For example, a wolverine sighted in California in 2008 was genetically traced back to Idaho, indicating dispersal rather than an established population. The elusive nature of these animals and their low population density, estimated at fewer than 300 individuals in the lower 48 states, make precise population counts challenging.
Understanding Wolverine Habitat Needs
Wolverines depend on specific environmental conditions that restrict their distribution to cold, high-elevation regions. A primary requirement is the presence of persistent deep snowpack, which they utilize for denning and caching food. Females construct natal dens within snow depths ranging from 3 to 16 feet, often under large boulders, fallen trees, or avalanche debris, where they give birth and raise their young through May. This deep snow provides insulation against cold temperatures and offers protection from predators.
These animals favor remote wilderness areas, specifically high-elevation alpine and subalpine forests, which typically have low human population density. Their need for expansive territories is also notable, with home ranges often spanning over a hundred square miles. Wolverines are opportunistic feeders, primarily relying on carrion, especially during winter, but also preying on small to medium-sized mammals like voles, rabbits, and hares.
Conservation Efforts for Wolverines
The wolverine population in the contiguous United States received protection as a threatened species under the Endangered Species Act. This designation acknowledges the significant threats facing these animals, particularly the ongoing impacts of climate change. Rising temperatures directly affect the deep, persistent snowpack essential for wolverine denning and food storage.
Beyond climate change, habitat degradation and fragmentation also pose substantial challenges to wolverine survival. Factors such as road construction, other forms of development, and disturbance from winter recreation further imperil their populations. The ESA listing provides important protections and resources aimed at mitigating these threats.
Conservation efforts include ongoing research, preservation of existing wolverine habitat, and initiatives to improve connectivity between fragmented areas. Managing human activity in their sensitive winter habitats is also a part of these protective measures. Scientists project that wolverines could lose approximately 23% of their habitat within the next three decades and up to 63% over the next 75 years due to climate change.