Arctic foxes are found in the treeless tundra extending through the arctic regions of Eurasia, North America, Greenland, and Iceland.

Biogeographic Regions: nearctic (Native ); palearctic (Native )

Other Geographic Terms: holarctic

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Circumarctic. In North America: northern and western Alaska and northern Canada south to northern Northwest Territories, northeastern Alberta, northern Manitoba, and northern Quebec; sometimes farther south.

Average mass: 5200 g.

Average basal metabolic rate: 7.665 W.

Length: 91 cm

Weight: 4000 grams

• Terrestrial
• Marine

Arctic foxes are found mainly in arctic and alpine tundra, usually in coastal areas.

Habitat Regions: polar ; terrestrial

Terrestrial Biomes: tundra ; icecap

Comments: Tundra, usually near shores. Ranges far out onto pack ice in winter. Commonly uses dumps in northern Alaska. When inactive, occupies underground den in bank or hillside; may tunnel into snowbank in winter. Breeding range in North America is mostly on the coastal plain and coastal regions of continental Canada and High Arctic islands. Young are born in underground dens. See Garrott et al. (1983) and Anthony (1996) for den site characteristics in northern and western Alaska, respectively.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Alaska, migrates seaward in fall and early winter, reverse movement in late winter and early spring. Long-distance movements of several hundred kilometers have been recorded (Underwood and Mosher 1982).

The arctic fox is an opportunistic feeder, eating practically any animal, alive or dead. Although it prefers small mammals, it will eat insects, berries, carrion, and even the stool of animals or human beings. Generally, its winter diet consists of marine mammals, invertebrates, sea birds, fish, and seals. For populations living more inland and in the summer, the diet consists mostly of lemmings. During the summer months, when food is much more readily available, arctic foxes collect a surplus amount of food and carries it back to their dens, where it is stored under stones for later use.

Animal Foods: birds; mammals; fish; eggs; carrion ; insects

Plant Foods: fruit

Other Foods: dung

Foraging Behavior: stores or caches food

Primary Diet: carnivore (Eats terrestrial vertebrates)

Comments: Opportunistic. Eats lemmings, voles, ground squirrels, young hares, birds, bird eggs, berries, carrion (e.g., leftovers from polar bear kills), and garbage when available; sometimes may prey on ringed seal pups in their subnivean birth lairs. May cache food, including bird eggs, for later use.

Relatively solitary, may congregate around carcass or dump. Home range much larger in winter than in summer. Based on a few radiotelemetry studies, adult home range is around 10-20 sq km. In Svalbard, mean home range of 3 breeding females was 48 sq km; home range estimates based on occupied dens were between 46 and 75 sq km; large size may have been due to relatively low food resources compared to other regions (Prestrud 1992). Populations vary, peak 1-2 years following peak in small mammal population. Populations in Fennoscandia may be limited by food availability via effects on reproduction (Angerbjorn et al. 1991). One den per 12-34 sq km in northern Alaska; density highest near development. One den per 24 sq km in Svalbard; for dens with litters, 1 den per 75 sq km (Prestrud 1992).

This is the most common predator of arctic birds (e.g., of black brant and lesser snow goose).

Comments: Activity cycles may peak at midnight or at midnight and noon (Underwood and Mosher 1982).

Average lifespan

Status: captivity: 16.3 years.

Arctic foxes are monogamous and usually mate for life.

Mating System: monogamous

Mating occurs from April to July, births take place from April through June for the first litter, and July or August for the second litter. The average gestation period is about 49-57 days. The number of young per litter varies with the availability of food, especially lemmings. The usual litter size is 5-8 cubs, although as many as 25 have been known. The young are weaned at about 2-4 weeks and emerge from the den. They reach sexual maturity in as little as ten months. The male parent stays with the cubs, helping to feed them. He mates with the female a few weeks after the first litter is born.

Range number of offspring: 1 to 5.

Average number of offspring: 2.8.

Range gestation period: 46 to 58 days.

Range weaning age: 28 to 60 days.

Average birth mass: 70 g.

Average number of offspring: 9.

Average age at sexual or reproductive maturity (male)

Sex: male: 304 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 304 days.

Parental Investment: altricial ; post-independence association with parents; extended period of juvenile learning

Monestrous, pair-bond may be lifelong. Usually breeds March- April. Gestation lasts 51-54 days. Litter size depends on food supply. Young are born April-June (appear above ground in June in northern Alaska), tended by both parents until mid-August. dispersal. Maximum recorded longevity was 6-7 years in northwestern Canada (Hiruki and Stirling 1989).

The arctic fox has been driven out of some regions, such as northern Scandinavia, because of predators like the red fox. The arctic fox has been hunted by humans for its pelt, and also hunted in Iceland because of being a pest to sheep farmers. Humans also keep arctic foxes in captivity in fur farms. Nevertheless, populations have remained relatively stable.

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Arctic Foxes face several types of threats resulting from global climate change. The most significant of these threats is probably the loss of the tundra habitat that the species inhabits. As warming temperatures allow new plant species from the south to colonize the region, large extents of tundra habitat are expected to slowly be replaced by boreal forest. Forest habitat is known to be highly unsuitable for Arctic Foxes (IUCN 2009).

Another threat to the Arctic Fox comes from Red Foxes, which compete with them for food and prey on Arctic Fox kits and adults. While the northern limits of the Red Fox’s range are determined by the productivity of the habitat, the southern limits of the Arctic Fox’s range are determined by the presence of the Red Fox. The encroachment of Red Foxes into more northern areas has already been documented and is likely to continue as the tundra warms (Fuglei and Ims 2008).

The changing climate also drives changes in prey abundance. Numbers of Arctic rodents, particularly lemmings, are known to fluctuate greatly, but historically such fluctuations have been fairly regular and cyclical. It is predicted, however, that climate change will lead to instability in the population sizes of these and other important prey species, such as voles. Lemmings and voles do not hibernate through the winter. Instead they continue to forage in the space between the frozen ground of the tundra and the snow, almost never appearing on the surface. This is possible because the snow provides good insulation from the severe Arctic winter conditions. Mild weather and wet snow lead to the collapse of these under-snow spaces, destroying the lemmings’ burrows, while ice crust formation reduces the insulating properties of the snow pack and may make food plants inaccessible. The combination of milder and shorter winters is predicted to decrease the regularity of lemming cycles, and population peaks in some populations have not occurred since the 1990s (IUCN 2009).

Any declines of important prey species are likely to have significant impacts on Arctic Fox populations. Declines of Arctic Fox numbers attributable to prey declines have already been observed in some Scandinavian populations. It is possible that although species such as lemmings may decrease in number, other potential prey species may begin to thrive in the new climate. Unfortunately for the Arctic Fox, the associated arrival of species such as the Red Fox would almost certainly cancel out any benefits from these changes (IUCN 2009). Arctic Foxes inhabiting coastal regions are likely to be less affected by declines of rodents than inland populations (Fuglei and Ims 2008). However, because Polar Bears and Ringed Seals are expected to decline due to climate change, coastal populations are likely to face reductions in alternative food sources such as Ringed Seal pups and the remains of Polar Bear prey (IUCN 2009).

Arctic Foxes are unable to persist in environments other than their native tundra habitat. This means that individuals living in southern parts of the species’ range will probably need to move north if they are to survive. Arctic Foxes, however, already occur in some of the most northerly parts of the world and their total available habitat is shrinking. This means that that the number of Arctic Foxes that can be supported worldwide is likely to decrease. Arctic Foxes living on Arctic islands may ultimately prove to be the safest of all populations. Such locations are generally at very high latitudes and will be among the last to face changes in tundra habitat and invasion by Red Foxes. Furthermore, the likely loss of the ice sheets currently connecting these islands to the continental landmasses will prevent access by Red Foxes (Fuglei and Ims 2008). However, island populations often tend to be more vulnerable to losses of genetic variation, which can cause health or reproductive problems.

Management Requirements: Removal or management of arctic foxes at or near brant colonies may increase nest success and assist re-establishment or expansion of depleted brant colonies; the same undoubtedly is true for seabird colonies (Raveling 1989, Anthony et al. 1991, Bailey 1993, Birkhead and Nettleship 1995).

Introduced, sterile red foxes have been used to eliminate introduced arctic foxes from some islands (Bailey 1992, 1993).

In Iceland, arctic foxes sometimes take lambs from sheep flocks. Farmers have been encouraged since the late thirteenth century to shoot and/or kill these predators in order to protect their livestock.

The fur of the arctic fox is prized by the fur industry, and these foxes have been intensively trapped. On the Pribiloff Islands of Alaska, arctic foxes have been regularly farmed for their fur since 1865, and they have long been important to the economy of the native people living withing their range.

Positive Impacts: body parts are source of valuable material

Comments: Commonly trapped for pelts (thousands each year in Alaska, tens of thousands per year in Canada) (Underwood and Mosher 1982); Sachs Harbour on Banks Island, Northwest Territories, is the most productive trapping area in Canada (Hiruki and Stirling 1989).

Species Impact: Introduced and/or colonizing populations on islands often have devastating effects on seabird communities (Lensink 1984, Bailey 1993, Birkhead and Nettleship 1995). Arctic foxes can limit numbers and distribution of nesting brant (Raveling 1989) and are regarded as an impediment to restoration of Aleutian Canada goose populations (Bailey 1992).

Comments: This species formerly was included in the genus Alopex. Data from chromosomes, mtDNA, and allozymes all indicate a close relationship among arctic fox, kit fox, and swift fox and do not support the recognition of the arctic fox in a genus separate from the kit and swift foxes (genus Vulpes) (Geffen et al. 1992, Mercure et al. 1993). The mammal lists by Baker et al. (2003) and Wozencraft (in Wilson and Reeder 2005) used the name Vulpes lagopus for the arctic fox.