Wolverines are powerful and elusive carnivores. Their solitary nature and remote habitats make understanding their populations a significant challenge for scientists. This difficulty in tracking and counting contributes to the uncertainty surrounding their exact global numbers.
Estimating Wolverine Populations
The world’s total wolverine population is not definitively known, as these animals exhibit low population densities and require vast home ranges. In the contiguous United States, current estimates suggest fewer than 50 individual wolverines, a notable decrease from an estimated 318 more than a decade ago. Other sources, however, refer to a slightly higher range of roughly 250 to 300 animals in the lower 48 states.
North America’s largest wolverine populations reside primarily in Canada and Alaska. In Scandinavia, which includes Norway, Sweden, and Finland, recent estimates from 2024 indicate a population of approximately 1,012 to 1,072 individuals, with Sweden accounting for 642 to 690 and Norway for 360 to 393. This figure shows a slight decrease from the previous year’s estimate of 1,028 to 1,115 individuals. Russia is believed to host the world’s largest wolverine population, though precise, current figures are scarce, and reports suggest a considerable decline over the past three decades.
Scientists employ various methods to estimate these hard-to-find populations. Non-invasive techniques, such as DNA sampling from hair snags and fecal matter, are commonly used to identify individual wolverines and track their movements. Camera traps, often combined with bait or scent lures, provide visual confirmation and assist in density estimation without direct animal contact. Researchers also monitor natal dens and track movements in snow to gather data, although these methods are limited by specific environmental conditions.
Despite these advanced techniques, challenges persist in obtaining accurate counts. Their vast territories make comprehensive surveys difficult, and their low population density means they are not abundant anywhere. The slow reproductive rate of wolverines and the non-overlapping ranges of same-sex adults add complexity to population assessment.
Where Wolverines Live
Wolverines inhabit remote regions across the Northern Hemisphere, displaying a circumpolar distribution. They are primarily found in northern boreal forests, subarctic, and alpine tundra environments. They thrive in mountainous areas and extensive wilderness, where cold temperatures and rugged terrain provide suitable conditions.
The largest concentrations of wolverines are located in northern Canada, the U.S. state of Alaska, the Nordic countries of Europe (Norway, Sweden, and Finland), and throughout western Russia and Siberia. In the contiguous United States, wolverine populations are known to exist in the North Cascades Range in Washington and the Northern Rocky Mountains, spanning Idaho, Montana, and a small part of Oregon. Individual wolverines have also been sighted in the Sierra Nevada mountains of California and the Southern Rocky Mountains in Colorado, although these areas do not currently support breeding populations.
Historically, the wolverine’s range in the United States extended much further south, reaching parts of the Midwest and Northeast. The availability of deep snow is particularly important, as it influences where these animals can establish their dens and find food.
Factors Influencing Wolverine Numbers
Wolverine populations have experienced a steady decline since the 19th century, with numbers decreasing in various parts of their global range. This trend is influenced by a combination of environmental and human-related factors that directly impact their survival and reproductive success.
Climate change represents a significant threat to wolverines, primarily due to their reliance on cold, snowy environments. Female wolverines require deep, persistent snowpack to create natal dens for birthing and raising their young, typically from February through May. As global temperatures rise, the melting of this snowpack directly reduces suitable denning habitat. Projections indicate that wolverines could lose a substantial portion of their habitat in the contiguous U.S., with estimates suggesting a 30% reduction within 30 years and up to two-thirds by the end of the century.
Additionally, wolverines cache food in snowbanks, using them as natural refrigerators to store provisions, which becomes difficult with warmer temperatures. Habitat loss and fragmentation further jeopardize wolverine populations. Development, resource extraction, logging, and the expansion of human settlements and transportation corridors break up the large, continuous wilderness areas these animals need. Roads, in particular, can act as barriers, limiting the movement and dispersal of wolverines, especially females, which affects genetic diversity and population connectivity.
Human-wildlife conflict also plays a role in suppressing wolverine numbers. Historically, unregulated trapping and poisoning campaigns severely reduced populations in many areas. While legal protections are now in place in some regions, incidental trapping still occurs. Poaching remains a concern in places like Russia, where wolverines are sometimes viewed as pests by hunters. Winter recreation activities can also disturb wolverine habitats, particularly during sensitive denning periods.
The availability of prey is another influencing factor, as wolverines rely on a diverse food base, including carrion from larger animals like wolves. Changes in the populations of other predators can indirectly affect the wolverine’s access to food resources.