THE PRIBILOF ARCTIC FOX

A small Fox, with a relatively compact body, short legs, round ears and a short snout. The largest subspecies of Arctic Fox, with a longer rostrum. Blue color phase predominates in this subspecies. Coat is thick and dense in winter, with a majority of this fur being fine underfur. Blue morph is brown tinged with a blue sheen in winter, changing to brownish dusky in summer, usually darkest on top of head and rump, with face and legs mixed with white hairs, and ears strongly edged with white. White morph is pure white in winter, the only marking being the small black nose pad, while in summer it is brown dorsally and light gray to white on its underside. Yellow eyes, with elongated pupils. Thickly haired feet. Tail is long and bushy. Females are slightly smaller than males, with 6 to 7 pairs of mammae.

About the species

Reproduction and behavior

Gestation: 51-54 days.
Young per birth: 7, up to 15.
Weaning: 28-35 days.
Sexual maturity: 9-10 months.
Life span: Unknown, probably around 10 years.
Breeding season: Between February and May.

Births take place from April to July. They den in sandy, well drained soils in low mounds and river cutbanks, and in coastal areas near food resources, such as seal rookeries. Social organization of this subspecies appears complex, and only a small percentage of adult and yearling female bred. A high degree of conspecific tolerance exists between certain individuals. Most nonbreeding Foxes attend the litters of breeding pairs. Attendant Foxes protect, play with, and probably feed pups. Old and sick individuals interact with pups at den sites and rendezvous areas. Yearlings of both sexes are widely tolerated near pups and breeding adults. Some yearlings attend multiple dens. Family units of Arctic Foxes aggregate during mating and pup rearing, then break up and are solitary during the fall and winter.

Diet and interaction with the environment

Opportunistic feeders, eating small mammals, birds, bird eggs, berries, carrion and garbage when available. Main predators: None. Exceptionally adapted for the extreme cold conditions of the Arctic region, with a highly insulating fur, compact body, foot thermoregulation and reduced metabolism during cold weather or food shortage. Mean home range size for both sexes is small relative to that reported for Arctic Foxes in other areas. Yearling home ranges show a large degree of overlap, while core areas are virtually discrete. Most yearlings engage in sporadic and unpredictable forays outside their normal home ranges, increasing in distance and duration over the summer.

Habitat:

Native to United States (Alaska). Restricted to the Pribilof Islands, on both St. George and St. Paul Islands. The habitat is associated with treeless coastal areas and sea ice.

Conservation status: Vulnerable. Regional status: low status and high biological vulnerability; action needed (USA). Populations of this subspecies are at critically low levels and appear to be declining further. The estimated population on St. Paul Island was 230 animals in 1991. Threats include significant reduction in food resources, increased exposure to diseases and toxins, and unsustainable levels of direct human persecution. Additionally, the decline in sea ice has likely led to increased genetic isolation. Misinformation as to the origin of Arctic Foxes on the Pribilofs continues to foster negative attitudes, and the long-term persistence of this endemic subspecies is in danger.