The Arctic fox ( Vulpes lagopus) thrives across the circumpolar Arctic, inhabiting the vast, treeless tundra and coastal regions. This remarkable mammal navigates one of Earth’s most challenging environments, showcasing exceptional adaptability. A key to its survival in these harsh conditions is its flexible and varied diet, which shifts significantly depending on season and food availability.
Primary Prey
Small rodents, particularly lemmings and voles, form the cornerstone of the Arctic fox’s diet across much of its range. These small mammals are so central to the fox’s sustenance that the white fox is often called the “lemming fox.” The availability of these prey species directly influences Arctic fox populations, as their reproduction rates often mirror the cyclical fluctuations of lemming densities. When lemmings are abundant, fox litters can be notably large, sometimes averaging seven pups and reaching up to fifteen or eighteen.
Conversely, during periods when lemming populations decline, Arctic foxes may produce fewer pups, or even none at all, due to food scarcity. This close predator-prey relationship underscores the lemming’s role as a keystone species, influencing the entire tundra ecosystem.
Seasonal and Opportunistic Foods
Arctic foxes are highly opportunistic omnivores, supplementing their primary diet with a wide array of other foods. In coastal areas, especially during summer, nesting seabirds such as auklets, puffins, and murres, along with their eggs, become significant food sources. Foxes also consume fish, marine invertebrates, and berries. Their diet can vary regionally; for instance, foxes in Iceland primarily consume birds, while those in Svalbard may rely heavily on geese and reindeer.
During the lean winter months, when small prey are less accessible, the Arctic fox shifts its focus to scavenging. They will readily consume carrion, including the remains of marine mammals, caribou, or reindeer. This adaptability ensures they can utilize almost any available edible item in their environment, even resorting to insects or plant matter like seaweed and berries.
Hunting and Scavenging Strategies
Arctic foxes employ specialized hunting techniques to secure their prey. Their acute hearing allows them to detect small mammals, such as lemmings and voles, moving up to two feet beneath layers of snow. Once prey is located, the fox uses a distinctive “snow diving” or “mousing” technique, leaping high into the air and plunging headfirst into the snow to capture its meal. An elongated snout, which generates less impact force upon penetration, helps protect them from injury during these dives.
Beyond active hunting, scavenging is a crucial survival strategy, particularly in winter. Arctic foxes often follow larger predators like polar bears and wolves, feeding on the leftover carcasses of seals or other large animals. This resourcefulness allows them to capitalize on kills made by others. Additionally, Arctic foxes practice food caching, burying excess food items, such as bird eggs or seabirds, in dens or under rocks. These larder hoards serve as vital reserves, providing sustenance during periods of food scarcity, especially in the long Arctic winter.