Wolverines depend on snow, and scientists have gathered evidence to show how much. Snow is crucial for wolverines: they use it for dens and for keeping food. In a study of 562 wolverine dens from Fennoscandia and North America, every one was at a site with snow that lasts into spring; most wolverine dens found so far are complexes of snow tunnels built next to boulders or rocks, and a mother wolverine can dig a snow den as deep as about 15 feet. A 2010 study proposed that wolverines are limited by their need for lasting spring snow for denning and by an upper limit of heat tolerance. It found that 95 percent of summer and 86 percent of winter tracking locations matched spring snow cover.
Wolverines are scarce and secretive, so they have been studied less than many other meat-eating animals. People rarely see wolverines because they are few and live in remote places. In North America, wolverines live mostly in Alaska and Canada, and they need large areas with few people. Wolverines live at low numbers everywhere in their range. Scientists use cameras that switch on by themselves to find wolverines. In winters 2016 and 2017, researchers in Idaho, Montana, Washington and Wyoming searched random 15-km by 15-km cells with cameras, and they detected wolverines in 59 of 183 cells, or 34 percent. In that four-state survey, 22,641 of 439,834 photos contained a wolverine, and at many stations most of those photos were of the same wolverine passing the camera again and again.
In the greater Yellowstone area, wolverines have been studied with live traps, radio tracking and aerial surveys. From 2006 to 2009, researchers documented seven wolverines in eastern Yellowstone and the national forests next to it. In that study, two females each used an average annual range of 172 square miles (447 km2), and three males used 350 square miles (908 km2). In Denali National Park, the home range of a wolverine may be 100 to 800 square kilometers, and a male wolverine needs a home range of hundreds of square miles. In 2008, a young male wolverine tracked by scientists traveled 585 miles over several months, ending in Colorado, the first documented wolverine there since 1919. Glacier National Park began a DNA-based wolverine monitoring program in 2009, then surveyed a 10 by 10 km grid of the park in the winters of 2011 and 2012.
Wolverines measure 65 to 105 cm in body length, with tails 13 to 26 cm long and shoulders 36 to 45 cm high. An adult male weighs about 12 to 18 kilograms (26 to 40 pounds), and adult females weigh about 8 to 12 kilograms (17 to 26 pounds), which is less than males. A wolverine has five toes on each foot, and it walks with its weight mostly on the long bones of its feet. That spreads its weight and helps it travel and hunt in snow. Its large paws work like snowshoes, and its long, curved claws help it climb. A wolverine's fur is dark brown, with a lighter yellow stripe along each side. Wolverines are sometimes called skunk bears because they look like small bears and give off a strong-smelling musk.
Wolverines mainly eat meat, but they also eat berries and other plant material. All year, they eat small and medium animals such as voles, squirrels, hares and birds, and a wolverine's strong teeth and powerful jaws let it eat even bone. Much of what a wolverine eats comes from animals that have already died. To scavenge is to eat what was left behind. Wolverines eat many kinds of meat, from ground squirrels and rodents to, sometimes, moose or caribou, but more often they scavenge carcasses left by other predators and store them for later. In winter, wolverines often eat the leftovers of moose and caribou that other animals left behind or that died naturally. Wolverines store extra food in holes or under the snow to eat later.
Wolverines mate in summer, but the fertilized egg does not start to grow until early winter, so the babies, called kits, are born between January and April. After a delay of about six months, a wolverine's pregnancy lasts only another 30 to 50 days, and counting the delay, it can last from 120 to 272 days. Delayed implantation lets wolverines have young when food is most plentiful and match the litter size to the food available. A mother usually has two to four kits, and newborn kits are blind and weigh less than one pound. Because litters are small and many young die, a female rarely raises more than one young that survives to have young of its own. Young wolverines are on their own by about five to six months old.
Wolverines were nearly gone from Montana in the early 1900s and have been increasing in numbers and range since. Trapping and predator control reduced their range in the lower 48 states by the 1930s, and some recovery has happened since. Long ago wolverines also lived farther south in Europe and the United States, but people's activities removed them from many of those places. As of November 2026, a 2017 to 2022/23 count put Europe's wolverines at about 1,300, in two groups: about 900 in Scandinavia, which is stable, and about 400 in Karelia, which is increasing. As of November 2026, Canada listed the wolverine as a species of special concern in 2018, and the United States named the lower 48 states' wolverines threatened in 2023. As of November 2026, the IUCN Red List labels the wolverine Least Concern, its lowest level of worry.
Wolverines usually live alone, and they make few sounds, only occasional grunts and growls; they have a very good sense of smell, and one account says a wolverine can smell a dead animal lying 20 feet under the snow. A wolverine can be active at any time of day or night, and wolverines stay active all year and do not hibernate. Wolverines can climb trees quickly and are excellent swimmers. In the wild, wolverines usually live 5 to 7 years, and a few reach 13. Frost does not build up on wolverine fur, so people in the Arctic have used it to trim the hoods of their coats. Snow is crucial for wolverines: they use it for dens and for keeping food, and their large paws work like snowshoes on deep snow.
Words to know
- scavenge: eat leftovers
- implantation: egg starting growth
- documented: officially recorded
- threatened: at risk
- kits: baby wolverines
