The arctic fox, Vulpes lagopus, is a resilient predator adapted to the extreme conditions of the Arctic environment. This species inhabits the vast, treeless tundra and coastal areas across the circumpolar North. Characterized by its dense fur, which changes color seasonally, the arctic fox plays a significant role as a generalist predator within the Arctic food web. Its survival in such a challenging habitat is largely attributed to its adaptability, particularly concerning its varied feeding strategies.
Primary Diet and Staple Prey
The core diet of the arctic fox consistently revolves around small rodents, primarily lemmings and voles, which represent their most reliable food source throughout their range. These small mammals are abundant in many Arctic regions, providing a high-energy food supply crucial for the fox’s survival and reproduction. The availability of lemmings often dictates the reproductive success and population density of arctic foxes, with their numbers fluctuating in multi-year cycles. When lemming populations are high, arctic foxes can have larger litters, while fewer pups are successfully reared when food is scarce.
Arctic foxes employ specialized hunting techniques to capture these elusive prey, even under snow cover. They possess keen hearing, allowing them to detect the faint sounds of rodents moving beneath several feet of snow. Once a sound is pinpointed, the fox will often perform a leap into the air, diving headfirst into the snow to seize its hidden meal, a technique known as “mousing.” This maneuver helps them break through the surface to reach the lemming’s tunnel or nest, showcasing their agility and precision.
When food is plentiful, arctic foxes cache surplus food. They bury individual items or larger quantities in the permafrost, in dens or among boulders, creating frozen pantries for later use. This behavior allows them to store food, providing a buffer during leaner times. The energy-rich nature of these small rodents supports the fox’s high metabolic rate, necessary for maintaining body temperature in sub-zero temperatures.
Seasonal and Opportunistic Feeding
The arctic fox’s diet diversifies with the changing seasons, showcasing its opportunistic nature and ability to exploit food sources. During the brief Arctic summer, when primary rodent populations might be less concentrated, foxes expand their foraging to include ground-nesting birds, their eggs, and young chicks. Species such as seabirds like auklets, puffins, murres, eiders, and geese become accessible prey during their nesting periods, especially for foxes denning near rocky cliffs.
The diet may also incorporate plant matter, such as berries, and insects, although these typically form a smaller portion of their overall intake. This seasonal shift allows the foxes to capitalize on the temporary abundance of different food items, supplementing their staple diet of rodents. The ability to switch between prey types demonstrates their flexibility in foraging behavior.
During the harsh winter months, when small rodent activity diminishes and snow cover deepens, arctic foxes often rely heavily on carrion. They frequently follow polar bears, scavenging the remains of larger marine mammals, such as seals, left behind after a bear’s kill. These leftovers provide a source of protein and fat during periods of extreme scarcity. Foxes may also hunt young ringed seal pups in their subnivean birth lairs.
Coastal arctic foxes exploit marine resources, preying on fish, shellfish, sea urchins, and other marine invertebrates washed ashore. This opportunistic behavior, including their reliance on scavenging and adapting to seasonally available prey, highlights the arctic fox’s resilience. Their ability to switch between diverse food sources ensures survival even when their primary prey is not readily available, making them well-suited for the Arctic environment.