Wolverine

Wolverines are opportunistic hunters, which means they eat whatever is available to them. Their diet can change with the seasons. Throughout the year, wolverines typically eat small to medium animals like voles, squirrels, hares, and birds. In winter, they often depend on the leftovers of moose and caribou that other animals have hunted or that died naturally. If the prey is weak or if there's deep snow, wolverines can even take down animals that are much larger than themselves, such as reindeer and elk.

At the Zoo, the wolverines receive a prepared ground carnivore diet, fish, rats, bones, and other food-based enrichment.

In North America, wolverines are found in Alaska, northern Canada, and some of the northern states in the western United States. Populations are also found in northern Europe and Eurasia, including Scandanavia and Russia.

Historically, the species was found in more southern parts of Europe and the United States. Unfortunately, during the 19th century, these populations were wiped out due to hunting and other human activities.

Found in alpine forests, tundra, and transition zone habitats at or above timberline. They prefer large, undisturbed areas with low human development. The species is found exclusively in areas with cold climates.

Wolverines have very few, if any, natural predators. They are impressively fierce and can defend themselves against animals several times their size. However, wolves, bears, mountain lions, and golden eagles can be threats to young or inexperienced wolverines.

Humans and human activity play the biggest threat to wolverines. Human encroachment, overhunting of both wolverines and their large prey, habitat fragmentation, and global warming all play a role in decreased wolverine populations.

Wolverine fur is usually darker brown with a yellowish stripe extending from the crown of the head, splitting over the shoulders and back end, then meeting back together at the tail. Their fur is long and dense for warmth in the cold environments they inhabit. They have stocky bodies with short, strong limbs. This keeps them low to the ground and they move in a loping gallop. The semi-retractable claws are long and curved, allowing them to climb and grip well. Large “snowshoe” feet enable them to walk on top of deep snow, rather than sinking.

Males and females come together briefly for mating, usually in the summer. Wolverines have delayed implantation, meaning the fertilized embryo is not implanted into the uterus to begin developing until early winter. This allows a female to become pregnant when food supplies are best and when she is in good physical condition. Females will often not produce young if food is scarce.

In winter, female wolverines build dens to store food and keep their young safe. They collect grasses and leaves to create comfortable nests in places like caves, rock crevices, and hollows under trees. Sometimes, they even dig burrows in packed snow. The babies, called kits, are born inside the den between January and April. On average, a female wolverine has two to four kits. These kits are born blind, weigh less than a pound, and have white fur. They start to eat solid food around 8 weeks old and become fully independent by the time they are about 6 months old.

Because of their scavenging lifestyle over very large ranges, wolverines have an excellent sense of smell. They generally communicate via scent glands and urine marking. They are rarely vocal, except for the occasional grunts and growls when irritated.

Wolverines are generally solitary and territorial. These territories can be very large; male wolverines can cover about 240 square miles, while females can cover around 100 square miles. Individuals will travel up to 25 miles in a day in search of food. Wolverines tolerate snow well and do not hibernate or migrate to avoid cold weather conditions. The wolverine can be active at any time during the day or night, year-round. Although generally found on the ground, they can climb trees quickly and are excellent swimmers.