Arctic foxes are predators that navigate the challenging, frozen landscapes of the Northern Hemisphere. These small canids thrive in the Arctic tundra, an environment characterized by extreme temperatures and fluctuating food availability. Their survival hinges on a flexible diet and specialized behaviors that allow them to locate and consume sustenance in a region where resources can be scarce.
Mainstays of the Menu
Arctic foxes primarily eat small mammals, particularly lemmings and tundra voles. These rodents are a staple food source, especially in summer. When lemming populations are abundant, they can constitute up to 70% of the fox’s diet. A family of foxes can consume dozens of lemmings daily during periods of high availability.
Arctic foxes also prey on ground-nesting birds, such as auklets, puffins, and murres, and their eggs. During the breeding season, bird eggs become an important food source, with a single fox potentially consuming over a thousand eggs. They also eat berries, seaweed, and various insects. Coastal populations may consume fish and marine invertebrates.
Adapting to the Seasons
The Arctic fox’s diet changes significantly with the seasons due to shifts in prey availability. During summer, when the tundra becomes more active, foxes primarily hunt small mammals, birds, and their eggs. This period of abundance allows them to build fat reserves. However, lemming availability can fluctuate in 3-5 year cycles, impacting fox reproduction and survival.
As winter arrives and prey becomes scarcer, Arctic foxes display opportunism. They frequently scavenge on carrion, including remains of seals and other marine mammals left by larger predators like polar bears. Foxes travel long distances across sea ice to follow polar bears and feed on their leftovers. This flexible approach helps them endure lean months.
Clever Foraging Techniques
Arctic foxes employ various methods to acquire food. They possess acute senses of hearing and smell, enabling them to locate prey, such as lemmings, moving in tunnels beneath snow. They can detect lemmings under 46-77 cm of snow and even subnivean seal lairs under 150 cm. Once prey is detected, the fox uses a characteristic “pounce” technique, often called “mousing.”
This involves listening intently, pinpointing the prey’s location, then leaping into the air, plunging headfirst into the snow to capture the animal. Research suggests foxes may even align their pounces with the Earth’s magnetic field to improve accuracy. Beyond active hunting, Arctic foxes cache food, burying excess, particularly bird eggs, during times of plenty. These caches serve as food reserves during scarcity, allowing them to survive harsh winters when other food sources are limited.