Gulo gulo

Some authors (e.g., Hall 1981) have regarded the North American wolverine as a species (Gulo luscus) distinct from the Eurasian wolverine (Gulo gulo). Most accounts treat luscus as a subspecies of Gulo gulo.

Large range in northern Canada and Alaska, where populations probably are in good condition; occurs also in northern Eurasia; status is not well known in many portions of the range; extirpated from most of range in contiguous United States, with promising signs of semi-recovery in selected western states.

Holarctic; northern Europe, northern Asia, and northern North America (Pasitschniak-Arts and Lariviere 1995, Aubry et al. 2007). The species occupies a wide elevational range; for example, in California, wolverines have been recorded at elevations of 400 to 4,300 meters (average 2425 m) (California DF&G 1990, Wilson 1982).

Historical range in North America: arctic islands to the mountains of California, Colorado, and Utah (Predator Conservation Alliance 2001), and parts of the northcentral and northeastern U.S. (where records are sketchy and scarce). Presently extirpated from most of the southern part of the range, including all of the northcentral and northeastern U.S. and most of southeastern and south-central Canada.

In Canada, the wolverine retains its original distribution in the arctic region and in the western mountain and boreal regions but has disappeared from the prairies and from areas south of the boreal forest in eastern Canada; within the boreal region a large gap distributional has developed southeast of Hudson Bay (Dauphine, 1989 COSEWIC report). There have been no verified reports of wolverines in Quebec since 1978, or in Labrador since 1950, but there are unconfirmed reports almost every year (Environment Canada, Species at Risk website).

Recent surveys in the contiguous United States indicate that wolverines appear to occupy (and are essentially limited to) the montane regions of Idaho, Montana, Wyoming, and Washington (Copeland 1996; Washington Department of Wildlife 1998; Inman et al. 2002; Giddings, pers. comm., 2003 cited by USFWS 2003; Squires, pers. comm., 2003, cited by USFWS 2003). Until recently, there had been no confirmed records of wolverine in California since 1922 (Grinnell et al. 1937); attempts to locate wolverines by means of photographic bait stations during the winters of 1991-1992 and 1992-1993 yielded no records (Barrett et al. 1994). In 2008-2010, a single male wolverine was photographed by camera traps in the central Sierra Nevada of California. However, genetic data indicate that this male is related to wolverines in the northern Rocky Mountains and not a remnant of the native California population. See Predator Conservation Alliance (2001) and Wilson (1982) for a state-by-state review of occurrence in the contiguous United States.

Data on the distribution in Eurasia are sketchy. The range in Scandinavia appears to be concentrated in the mountainous central and northern portions of Norway and Sweden, as well as in Finland (Kvam et al. 1988; Nyholm 1993 and Andersson 1995, cited by Blomqvist 1995). Wolverines also occupy the taiga and northern coniferous forest of the former Soviet Union (M. S. Blinnikov, pers. comm.). [from Petersen 1997]

Number of occurrences is unknown but there are many in North America and Eurasia. However, occurrences must be defined on a very large scale, so the number of distinct occurrences in a large region will be one or a few at most.

Decline may have been due primarily to fur trapping. Habitat has been degraded through timber harvesting, ski area construction, road construction, and general human disturbance (Biosystems Analysis 1989). There are conflicts with backcountry trappers.

Excessive hunter harvesting and loss of ungulate wintering areas (Banci 1994), as well as displacement of ungulate populations due to excessive timber harvest and urbanization, may adversely impact wolverines (www.wolverinefoundation.org).

In western Canada, with the extensive human settlement that began in the mid-19th century, the wolverine has undergone range contractions and population reductions. Wolf control programs that were in effect from the 1950s and into the 1990s contributed to this species' decline. The habitat, particularly in the southern part of the range, is subject to loss, degradation, and fragmentation from oil, gas, and mineral exploration and extraction, forestry, roads, agriculture, and urban development. Although Wolverines are known to use snowmobile trails and scavenge from traps, backcountry recreation can lead to habitat alienation for these secretive animals. Increased access of motorized vehicles into remote areas may also increase harvest pressure on the wolverine and on its ungulate prey, particularly the threatened Southern Mountain population of Woodland Caribou. In the arctic tundra, developments frequently attract wolverines, which are then at risk of being killed as nuisance animals. As an economically valuable furbearer, the wolverine is subject to trapping and has been over-harvested in some areas. Declines in the population in eastern Canada are related to a combination of factors: hunting and trapping in the late 19th century, dwindling caribou herds in the early 20th century, human encroachment on habitat, reduction in the number of wolves, and the indiscriminate use of poison baits. [From Environment Canada Species at Risk website. See Dauphine (1989 COSEWIC report) for further information on threats in Canada.]

Among the limiting factors in Alberta are the loss of isolated habitat, a reduction in the availability of large ungulate carrion, and trapping pressure (Petersen 1997).