What Do Arctic Foxes Eat? Diet on the Tundra and Sea Ice

Lemmings: the main food on the tundra

For Arctic foxes living on the mainland tundra of North America, Russia and Scandinavia, lemmings are the most important prey, followed by voles. When lemmings are plentiful, a fox family raising pups can eat dozens of them a day.

Hunting lemmings in winter takes skill. The rodents live in tunnels under the snow, so the fox listens for their movements, pinpoints the sound, then jumps high and plunges down with its front feet and nose to break through the snow and pin its prey. In summer, when lemmings are above ground, foxes simply chase them down or dig them out of burrows.

How lemming cycles shape the fox’s life

Lemming numbers rise and crash in cycles that peak roughly every three to five years. Inland Arctic foxes, most of which are the white color morph, track these cycles closely. In a peak year a pair can raise a huge litter, sometimes more than ten pups. When lemmings crash, many foxes do not breed at all, and young foxes may starve or set off on long journeys in search of food, sometimes across the sea ice.

In some parts of the Arctic these cycles have become weaker or irregular in recent decades, which scientists link partly to warmer, wetter winters that damage the snow layer lemmings rely on. Fewer good lemming years means fewer successful fox breeding seasons.

Seabirds, eggs and fish on the coast

Arctic foxes on coasts and islands, where the blue color morph is common, rely much less on lemmings. Instead they feed on seabirds, their eggs and chicks, especially beneath busy bird cliffs and in colonies of geese, eiders and other ground-nesting birds. In Iceland and on Svalbard, birds make up much of the diet in summer. Coastal foxes also eat fish, mussels and other shellfish, small crustaceans washed up on the shore, and the carcasses of seals, whales and seabirds.

Because the coast offers a steadier supply of food than the lemming cycle, coastal foxes usually raise moderate litters every year instead of boom-and-bust families.

Following polar bears across the sea ice

In winter and spring some Arctic foxes travel far out onto the sea ice. There, the main source of food is the polar bear. A polar bear often eats only the fat and skin of a seal and leaves the rest, and foxes trail behind bears to clean up the leftovers. This partnership is one-sided: the bear gains nothing, and a careless fox risks being killed.

Arctic foxes also hunt on the ice themselves. In April and May they dig ringed seal pups out of the snow lairs where mother seals give birth. See what polar bears eat for the other side of this food web.

Carrion and other foods

Arctic foxes are not fussy. They eat almost any animal they find dead, including reindeer and caribou that die in winter, which can be an important food source on islands such as Svalbard. They will also eat insects, berries such as crowberries and bilberries in late summer, and seaweed. In very hard times they have even been recorded eating the droppings of other animals.

Caching food for winter

Summer in the Arctic is short but rich, and Arctic foxes make the most of it by storing food. They bury lemmings, young birds and especially eggs in small caches scattered around their territory, often hundreds of them.

Research in snow goose colonies in the Canadian Arctic has shown just how important this is. Foxes there take eggs at a high rate during the nesting season and cache most of them instead of eating them right away. Cold ground keeps the eggs well preserved, so a buried goose egg loses only a small part of its food value after two months, and foxes dig up cached eggs in winter and even the following spring, just before they breed.

How Arctic foxes compare with other foxes

All foxes are flexible feeders, but the Arctic fox’s diet is more strongly tied to a few prey types and to the seasons than that of most of its relatives. The red fox eats more fruit and a wider range of prey, while the fennec fox of the Sahara relies heavily on insects. For a broader look at fox diets, see what do foxes eat?.