Arctic foxes eat a remarkably wide range of food, from lemmings and voles to seabirds, fish, seal carcasses, goose eggs, and even muskox carrion. Their diet shifts dramatically with the seasons, the landscape they inhabit, and how many lemmings happen to be around in a given year. That flexibility is central to how they survive in one of the harshest environments on the planet, where food can be abundant for a few summer weeks and then vanishingly scarce for months of polar darkness.
Lemmings and the Rodent Cycle
If arctic foxes have a signature meal, it is the lemming. Across most of the species’ range in Scandinavia, Canada, Russia, and Greenland, lemmings and voles form the backbone of their diet when these small rodents are available. Lemming populations famously boom and bust in roughly three- to five-year cycles, and the lives of arctic foxes track those cycles almost perfectly. During peak lemming years, foxes breed more successfully, produce larger litters, and generally thrive. One study in Scandinavia found that reproductive success was significantly higher at dens located in lemming-rich areas during peak years, though the advantage disappeared during low and increase phases of the cycle.1Polar Biology. Effects of habitat characteristics and spatiotemporal variation in prey on reproductive success in the Arctic fox (Vulpes lagopus)
When lemming populations crash, the consequences ripple outward. Foxes that relied on rodents are forced to hunt harder, travel farther, and eat whatever else they can find. This is when their dietary flexibility becomes a survival trait rather than a curiosity. In lean years, foxes pivot to birds, eggs, fish, invertebrates, berries, and scavenged carcasses of larger animals. The degree to which a fox population depends on lemmings versus other food sources varies enormously by geography, which brings up one of the most interesting splits in arctic fox ecology.
Coastal Foxes Versus Inland Foxes
Arctic foxes living near coastlines eat very differently from those living inland. Research in Iceland has documented this divide clearly: coastal foxes feed primarily on prey derived from the ocean, especially seabirds and seal carcasses, while inland foxes depend on migrant birds like geese, waders, and passerines during summer and switch to ptarmigan in winter.2Journal of Zoology. Diet of arctic foxes (Alopex lagopus) in Iceland This is not a subtle preference. Chemical analysis of fox tissues shows that coastal and inland foxes carry fundamentally different isotopic signatures, reflecting the marine-versus-terrestrial split in their diets. Coastal foxes in Greenland, for instance, had carbon isotope values typical of marine food webs, while inland foxes in Iceland and Sweden showed values typical of terrestrial ones.3PubMed. Dietary variation in arctic foxes (Alopex lagopus)-an analysis of stable carbon isotopes
Icelandic foxes fall along a gradient between these two extremes, with coastal individuals clustering near marine prey signatures and inland individuals at the terrestrial end.4bioRxiv. Long-term responses of Icelandic Arctic foxes to changes in marine and terrestrial ecosystems The takeaway for anyone trying to answer “what do arctic foxes eat” is that the question almost demands a follow-up: where? A fox living on the coast of Svalbard and a fox living on the inland tundra of Canada may share a species name but barely share a menu.
Iceland is an especially useful case study because it lacks lemmings entirely. Without rodents to anchor the diet, Icelandic foxes have organized their feeding ecology around what the landscape offers: the ocean’s bounty along the coast and migratory birds and ptarmigan inland. This shows that the lemming-centric picture of arctic fox feeding, while accurate for much of the Arctic, is not the whole story.
How the Menu Changes Through the Year
Even within a single location, what an arctic fox eats in April can be strikingly different from what it eats in September. Molecular analysis of fox droppings in northeast Greenland captured these seasonal swings in detail. In late winter, muskox carrion dominated the diet, supplemented by smaller amounts of waterfowl, ptarmigan, lemmings, and fish. As spring arrived and snow receded, muskox became less frequent while waterfowl, fish, and lemmings took over. Hares and small songbirds also appeared in the summer diet. By September the mix shifted again toward muskox carrion, wading birds, and fish. October looked a lot like late winter: mostly muskox and fish, with some waterfowl still in the picture.5Polar Science. Spatio-temporal patterns in arctic fox (Vulpes alopex) diets revealed by molecular analysis of scats from Northeast Greenland
The pattern makes intuitive sense. Muskoxen are large animals that die in winter from cold, starvation, or predation by wolves, and their frozen carcasses persist as a food source through the lean months. When migratory birds flood the tundra in late spring and summer to breed, foxes take advantage of the seasonal glut of eggs, chicks, and adult birds. As those birds leave in autumn, the fox diet loops back to scavenging and whatever small mammals are available. Arctic foxes do not have the luxury of being picky, and the Greenland data makes this clear: their diet is a running negotiation with whatever the season provides.
Raiding Nesting Colonies
Birds that nest on the Arctic tundra have very good reason to worry about foxes. Arctic foxes are major predators of goose nests, and the intensity of that predation depends on, once again, lemmings. During peak lemming years, foxes are busy eating rodents and leave goose nests relatively undisturbed. When lemmings are scarce, foxes turn to eggs and goslings with enthusiasm. Research in the Canadian Arctic found that predators consumed anywhere from about 19% to 88% of annual goose nesting production, with egg predation intensity varying nearly threefold. The lowest predation occurred in peak lemming years, and arctic foxes were identified as one of the key predators driving that variation.6Journal of Animal Ecology. Shared predators and indirect trophic interactions: lemming cycles and arctic‐nesting geese
This dynamic creates an indirect link between lemmings and geese that biologists call apparent competition. Geese do not compete with lemmings for food or space, but they share a predator. When lemming numbers crash, the predator pressure that was directed at rodents swings over to the nearest alternative prey, and nesting birds take the brunt of it. For species like snow geese and brant that breed in dense colonies on open tundra, a low-lemming year can mean catastrophic nest failure. Foxes do not just eat eggs opportunistically either; they cache them, burying surplus eggs in shallow soil or permafrost for later retrieval. This caching behavior allows a single fox to harvest dozens or even hundreds of eggs from a colony over a few days of intensive raiding.
Hunting Under the Snow
One of the most visually striking things arctic foxes do is mouse. The fox listens carefully, pinpointing a rodent moving beneath the snowpack, then leaps high into the air and plunges headfirst into the snow. This plunge-diving behavior has been studied using biomechanical modeling, and it turns out that the fox’s slim, narrow facial structure plays a direct role in making it work. Both arctic and red foxes dive into snow at speeds of roughly two to four meters per second, and the streamlined skull helps the fox penetrate the snowpack efficiently rather than being deflected.7PubMed Central. Effect of skull morphology on fox snow diving
Mousing is primarily a winter and early-spring behavior, used when rodents are active in tunnels beneath the snow but invisible from above. The fox relies heavily on hearing to locate prey, and experienced individuals can be startlingly accurate. In summer, the same foxes simply chase lemmings across open ground, which requires less acrobatic skill but benefits from the fox’s speed and endurance across tundra terrain.
Scavenging and Carrion
Scavenging is not a secondary survival strategy for arctic foxes; for much of the year, it is a primary one. Muskox and reindeer carcasses are critical food sources through the winter months, especially in areas where rodent populations are low. Arctic foxes share these carcasses with other predators, including red foxes, wolverines, and ravens. A study in Fennoscandian low-Arctic tundra found that competition at carcass sites increased the likelihood that both arctic and red foxes would leave an occupied carcass between consecutive weeks. Interestingly, this competitive avoidance appeared to be symmetrical: neither species dominated the other at individual carcass sites, though the broader population-level dynamics between the two species tell a more complicated story.8PubMed Central. Effects of resource availability and interspecific interactions on Arctic and red foxes’ winter use of ungulate carrion in the Fennoscandian low-Arctic tundra
Arctic foxes have also been documented following polar bears and feeding on seal carcasses the bears leave behind. In coastal areas, beached marine mammals, dead fish, and invertebrates washed ashore provide additional scavenging opportunities. The common image of the arctic fox as a fierce little hunter is true enough in summer, but in the deep of winter, scavenging is often what keeps the animal alive.
Competition With Red Foxes
The relationship between arctic foxes and red foxes is one of the more consequential dynamics shaping arctic fox diets today. Red foxes are larger, more aggressive, and have been expanding northward into tundra habitats, pushing arctic foxes to higher altitudes and more marginal terrain in parts of Scandinavia.9Canadian Journal of Zoology. Food-niche overlap between arctic and red foxes Where the two species overlap, there is real dietary overlap too. In Prudhoe Bay, Alaska, researchers found moderate overlap in the diets of both species, though red foxes appeared more specialized on lemmings while arctic foxes had a broader diet.10Canadian Journal of Zoology. Anthropogenic food use and diet overlap between red foxes (Vulpes vulpes) and arctic foxes (Vulpes lagopus) in Prudhoe Bay, Alaska
That finding runs counter to what many people might expect. You might assume the smaller arctic fox would be the scrappy generalist forced to eat whatever the red fox leaves behind, and in one sense that is true: arctic foxes are pushed to less productive habitats. But in terms of actual diet breadth, the arctic fox is the more flexible eater. The red fox in Prudhoe Bay concentrated on lemmings while the arctic fox spread its foraging across a wider range of prey items. Whether that dietary flexibility is an advantage or simply a necessity imposed by being outcompeted for the best hunting grounds is an open question.
Human Food and Industrial Sites
Where arctic foxes live near human infrastructure, they take advantage of it. In the Prudhoe Bay oilfields, both arctic and red foxes consumed anthropogenic food, meaning garbage, discarded food, and other human-associated waste. The proportion was modest in late summer, roughly 10% to 15% of diet for both species, but in late winter it climbed to about 39% for arctic foxes and 49% for red foxes.10Canadian Journal of Zoology. Anthropogenic food use and diet overlap between red foxes (Vulpes vulpes) and arctic foxes (Vulpes lagopus) in Prudhoe Bay, Alaska Late winter is exactly when natural food is scarcest, so the timing makes sense: foxes near human camps supplement their diet with whatever is available when lemmings and birds are not.
This has management implications. Human food subsidies can artificially inflate predator populations, which then exert greater pressure on prey species like nesting birds and lemmings. They can also draw red foxes farther into arctic fox territory, intensifying the competitive dynamic between the two species. Waste management at Arctic industrial sites and research stations is, from a wildlife perspective, a fox management issue.
Climate Change and the Disruption of Rodent Cycles
The warming Arctic is changing what foxes eat by changing what is available. One of the most important mechanisms runs through lemming cycles. Warmer winters alter snowpack quality, and lemmings depend on stable, insulating snow cover to breed successfully beneath the surface during winter. When warm spells cause snow to melt and refreeze into hard ice layers, lemming populations cannot reach the high peaks they once did.11Journal of Mammalogy. Arctic fox winter dietary response to damped lemming cycles estimated from fecal DNA In the short term, warmer winters have been linked to missed lemming peaks and reduced arctic fox breeding success.12PubMed Central. Global warming and effects on the Arctic fox
Modeling work on high-Arctic predator-prey dynamics has gone further, suggesting that climate change lengthens the lemming population cycle and decreases the maximum densities lemmings reach. Because arctic foxes have evolved to capitalize on boom years, those flattened peaks are particularly damaging to their reproductive output and population densities. Under many plausible climate scenarios, the models project that reduced prey availability could eventually lead to local extinction of some Arctic predator species.13Global Change Biology. Climate change and cyclic predator–prey population dynamics in the high Arctic The arctic fox’s dietary flexibility may buffer it for a while, and the research from Greenland on seasonal diet switching suggests these foxes are capable of leaning on alternative prey. But flexibility has limits, and researchers have emphasized that the availability of alternative prey will become increasingly important as the Arctic continues to warm.11Journal of Mammalogy. Arctic fox winter dietary response to damped lemming cycles estimated from fecal DNA
Energy Balance in Extreme Cold
Understanding what arctic foxes eat also means understanding how much energy they need and how that changes through the year. Research on captive arctic foxes in Svalbard found that their body mass and food intake follow strong seasonal patterns, peaking in autumn as the foxes build fat reserves and declining through winter. The relationship between starvation and cold is not straightforward: during an extremely cold November, researchers observed that the foxes did not enter the metabolic depression that might have been expected during food restriction. Instead, the extreme cold appeared to mask any energy-saving response, because the foxes needed to maintain heat production just to stay alive.14PubMed. Seasonal trends in body mass, food intake and resting metabolic rate, and induction of metabolic depression in arctic foxes (Alopex lagopus) at Svalbard
This helps explain why winter food scarcity is so dangerous. An arctic fox cannot simply slow down its metabolism and wait for spring when ambient temperatures are far below freezing. It needs calories to generate heat, which means it needs to find food even in the darkest, coldest months. Scavenging carcasses, raiding cached food stores, and exploiting any human food waste nearby are not optional strategies during this period. They are the difference between surviving the winter and not.
How Fox Diets Shape the Tundra
The connection between arctic foxes and their food runs in both directions. By dragging prey back to their dens, defecating there, and caching food in the surrounding soil, foxes concentrate nutrients in landscapes that are otherwise extremely nutrient-poor. Research in the Canadian Arctic found that soils on fox dens had dramatically higher nutrient levels than surrounding tundra: in August, den soils contained roughly two and a half times more inorganic nitrogen and nearly twice as much extractable phosphorus as nearby control sites. The result was about 2.8 times greater vegetation biomass on dens compared to the surrounding landscape.15PubMed Central. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens
These nutrient hotspots make fox dens stand out visually on the tundra as bright green patches of lush vegetation surrounded by sparse ground cover. The dens then attract other wildlife, including herbivores drawn to the richer plant growth and invertebrates thriving in the more fertile soil.16Global Ecology and Conservation. Foxes engineer hotspots of wildlife activity on the nutrient-limited Arctic tundra Arctic fox dens have been used for centuries, sometimes millennia, and the accumulated nutrient deposits turn each den into a small, self-sustaining oasis. The foxes’ diet, in other words, does not just sustain the fox. It fertilizes the tundra and reshapes the local ecosystem around every active den site.