The wolverine, Gulo gulo, is the largest terrestrial member of the Mustelidae, or weasel family. This medium-sized carnivore is built with strength and tenacity, allowing it to survive in some of the world’s most challenging environments. It inhabits the remote, harsh northern latitudes, including the taiga, tundra, and boreal forests of North America and Eurasia. Its dietary habits are highly opportunistic, reflecting the scarcity and seasonal availability of food.
Primary Diet: Scavenging and Winter Reliance
The wolverine’s primary dietary strategy is that of an opportunistic scavenger, a behavior that is particularly important during the long winter months. They are highly adapted to locate and consume carrion, often relying on the remains of large ungulates like moose, elk, and caribou. These carcasses are frequently found after a natural winter-kill event or left behind by larger predators, particularly wolf packs.
Their strong sense of smell allows them to detect buried or frozen animal remains from miles away, sometimes under several feet of snow. Once a carcass is located, the wolverine uses its powerful jaws and specialized molars to process frozen flesh and bone, maximizing the nutritional intake from a single meal.
The wolverine exhibits caching behavior, burying excess meat in the snow or earth. This action effectively refrigerates the food, preserving it for later consumption during times of scarcity. Their wide, snowshoe-like paws allow them to travel efficiently over deep snow, giving them an advantage when accessing frozen food sources in the depths of winter.
Active Hunting and Small Prey
While carrion sustains them through winter, wolverines are also powerful and versatile hunters when scavenging opportunities diminish. They actively pursue and kill small to medium-sized mammals, which form a significant part of their diet throughout the year. Their prey includes snowshoe hares, marmots, ground squirrels, voles, and mice.
The wolverine’s hunting style often capitalizes on the vulnerabilities of its prey. They use their digging ability to unearth rodents hibernating or burrowing beneath the snow. They also prey on birds, consuming eggs and fledglings during the spring and summer breeding seasons. In deep, soft snow conditions, they can sometimes take down struggling large prey, such as weakened deer or young reindeer calves.
In North America, the diets of wolverines show a high proportion of species like the hoary marmot or snowshoe hare, depending on the region’s local abundance. Wolverines in Eurasian regions, such as Fennoscandia, are noted to hunt more actively than their North American counterparts due to different competitive dynamics with other predators.
Plant Matter and Supplemental Foods
Although the wolverine is primarily a meat-eater, its diet includes various supplemental non-meat items. These foods are consumed seasonally, providing necessary micronutrients that complement their protein-heavy diet. Plant matter typically makes up a minor portion of their overall intake compared to meat.
Berries are a notable supplemental food, often eaten during late summer and early autumn when they are readily available. They also occasionally consume roots and tubers dug out of the ground. Insects and grubs are sometimes sought out as an easily accessible food source, especially when the wolverine uses its claws to tear apart old stumps or logs.