Arctic fox - © Love Dalén
English: Arctic fox, Polar fox; French: Isatis, Renard Polaire, Reynard Polaire; German: Polarfuchs; Icelandic: tófa; Swedish: fjällräv; Indigenous names: Saami:njálla, svála.
The Arctic Fox has a circumpolar distribution in all Arctic tundra habitats, with a global population in the order of several hundred thousand animals. Most populations fluctuate widely in numbers between years in response to varying lemming numbers. In most areas population status is believed to be good.
The Arctic Fox has a circumpolar distribution in all Arctic tundra habitats. It breeds north of and above the tree line on the Arctic tundra in North America and Eurasia and on the alpine tundra in Fennoscandia, ranging from northern Greenland at 88°N to the southern tip of Hudson Bay, Canada, 53°N. The southern edge of the species' distribution range may have moved somewhat north during the 20th century resulting in a smaller total range (Hersteinsson and Macdonald 1992). The species inhabits most Arctic islands but only some islands in the Bering Strait. The Arctic Fox was also introduced to previously isolated islands in the Aleutian chain at the end of the 19th century by fur industry (Bailey 1992). It has also been observed on the sea ice up to the North Pole.
Habitat and Ecology:
Arctic and alpine tundra on the continents of Eurasia, North America and the Canadian archipelago, Siberian islands, Greenland, inland Iceland and Svalbard. Subarctic maritime habitat in the Aleutian island chain, Bering Sea Islands, Commander Islands and coastal Iceland.
The Arctic Fox is an opportunistic predator and scavenger but in most inland areas, the species is heavily dependent on fluctuating rodent populations. The species' main prey items include lemmings, both Lemmus spp. and Dicrostonyx spp. (Macpherson 1969; Angerbjörn et al. 1999). In Fennoscandia, Lemmus lemmus was the main prey in summer (85% frequency of occurrence in faeces) followed by birds (Passeriformes, Galliformes and Caridriiformes, 34%) and reindeer (Rangifer tarandus) (21%; Elmhagen et al. 2000). In winter, ptarmigan and grouse (Lagopus spp.) are common prey in addition to rodents and reindeer (Kaikusalo and Angerbjörn 1995). Changes in fox populations have been observed to follow those of their main prey in three- to five-year cycles (Macpherson 1969; Angerbjörn et al. 1999).
Foxes living near ice-free coasts have access to both inland prey and sea birds, seal carcasses, fish and invertebrates connected to the marine environment, leading to relatively stable food availability and a more generalist strategy (Hersteinsson and Macdonald 1996). In late winter and summer, foxes found in coastal Iceland feed on seabirds (Uria aalge, U. lomvia), seal carcasses and marine invertebrates. Inland foxes rely more on ptarmigan in winter, and migrant birds, such as geese and waders, in summer (Hersteinsson and Macdonald 1996). In certain areas, foxes rely on colonies of Arctic geese, which can dominate their diet locally (Samelius and Lee 1998).