Spirit of the Tundra

Natural History, Dec, 1998 by J. David Henry

There are limits to how far north red foxes can survive, but where the two species do overlap, arctic foxes are in danger of being replaced by their larger relatives, which often outcompete the arctic foxes for food and denning sites and sometimes prey directly upon them. A well-documented--if somewhat unnatural--example may be found on the Pribilof and Aleutian Islands off the west coast of Alaska. During the 1920s and 1930s, when the price for fox pelts was high, arctic and red foxes were released onto these islands in an effort to develop open-range fox farms. Biologists are now painfully aware of the havoc these foxes cause to populations of breeding birds and, for several decades and at a cost of thousands of dollars, have tried to rid the islands of foxes. Although largely unsuccessful, their efforts have been revealing: whenever the two species were placed on the same island, red foxes consistently replaced arctic foxes. So, in 1984, taking advantage of the red foxes' ability to dominate their smaller relatives, biologists introduced sterilized red foxes into two Aleutian Islands that previously had only arctic foxes. By the summer of 1992, the arctic fox was gone from both islands, and the sterilized red foxes will soon die out.

Competition with, and predation by, red foxes may be among the several problems facing arctic foxes in parts of Scandinavia. The arctic fox was an important furbearer in Norway, Sweden, and Finland until the 1920s, when its numbers crashed. Hunting and trapping were subsequently banned, but more than half a century of legal protection has not restored arctic fox populations. A number of interacting factors may be keeping their numbers down. A serious reduction in the wolf population has meant fewer wolf-killed car-casses for the foxes to scavenge. Climatic warming may favor red foxes. Interbreeding with arctic foxes that have escaped from fox farms and may no longer be genetically well adapted to the wild may be weakening the species. And certain pathogens and diseases, such as sarcoptic mange, are known to have spread from red or farm-bred foxes to wild individuals.

In Iceland, where there are no red foxes, the arctic fox is generally regarded as vermin because it preys on eider ducks (many farmers supplement their income by harvesting eiderdown every summer); arctic foxes are also accused of killing lambs and even sheep. Under present law, communities in Iceland must hire one or more hunters each spring to visit all known fox dens in the area and, if possible, kill any occupants. During the 1960s and 1970s, such actions reduced the country's arctic fox population by as much as two-thirds. In the past few years, wildlife managers have been releasing sterilized adult male arctic foxes from fox farms. Larger than the wild males, these foxes are expected to be more successful at controlling territories and attracting mates. This biological control technique may reduce Iceland's arctic fox populations even further.

The arctic fox is not yet a rare species, however. In Russia, the species has been replaced by the red fox in some areas but is still found throughout the far north, being especially common toward the coast. Arctic foxes are also common along the coast of Greenland. Replacement of arctic foxes by red foxes has been a problem in parts of Quebec, but arctic foxes inhabit virtually all of Canada north of the tree line--from the Yukon to Labrador--and have been carried on ice floes to Newfoundland and Cape Breton Island. In Alaska, the arctic fox lives in coastal and tundra regions in the western and northern parts of the state and is periodically abundant north of the Brooks Range.