Gulo gulo

The wolverine is possibly the least known of the northern hemisphere's large carnivores (2). Individuals are solitary, except for mothers with their young, and can occupy enormous home ranges depending on habitat and prey availability. Male's home ranges may encompass those of several females, and the largest have been estimated at around 920 km2 (3). Wolverines tend to alternate periods of activity and sleep throughout the day and night, when awake they are capable of crossing vast distances, climbing trees and swimming rivers (3). Mating occurs from April to August and births take place the following spring, usually within a den or sheltered area appropriated by the mother (4). Litters typically contain two to three cubs, which are born blind and with white fur. Weaned after nine to ten weeks, cubs often stay with their mother for over a year and females are therefore likely to reproduce only every couple of years (4). Wolverines are reputed to have a voracious appetite and are even known as the 'glutton' in some areas (3). They do not hibernate over the cold winter months as some other carnivores do and are opportunistic scavengers, often feeding on carrion (3). The diet varies across their range with wolverines in Scandinavia feeding on wild and domestic reindeer (4), and those in Alaska consuming whale and seal carcases (3). Food may be stored for later consumption but wolverines also actively attack some prey, especially smaller mammals such as domestic sheep (4).

Wolverines are widely distributed in the northern reaches of both hemispheres. In North America, they occupy remote habitats from the high mountainous interior of the Rockies to Arctic coastal tundra. They are solitary wanderers who specialize on larger vertebrate prey. They usually feed on small-to-medium size mammals, but have even been known to take down caribou, and will eat carrion. Wolverines use large home ranges of 100 to 600 square km. Males are larger than females, and their ranges are larger; a male will exclude all other males from his range, but his territory may overlap with that of several females.

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The elusive wolverine has a fearsome reputation - it is the largest member of the weasel family. The remoteness and voracious appetite of these creatures have led to an aggressive reputation. Males are much heavier than females and both have a stocky body and short legs (3). They are well adapted to the cold habitat of their northern range with a thick, bushy coat and broad, hairy paws (3). The glossy coat is dark brown with a paler stripe across the rump and along the sides of the body; some individuals have white throat patches (4). The powerful jaws and large teeth are able to demolish frozen carrion and bone (3). Wolverines carry their head and tail lower than the arched back and their gait appears somewhat humpy and lumbering although they can move very quickly when necessary (3).

More info for the term: tundra

The wolverine is a circumpolar species occurring primarily in boreal and tundra ecosystems of North America, Europe, and Asia. In North America, the distribution extends from the Aleutian Islands of Alaska east through Canada and south to the northern Rocky Mountains. Verifiable sightings within the United States since 1985 occurred in Montana, Idaho, Washington, Oregon, Wyoming [5,31], and Alaska [42,75]. Based on genetic records, a wolverine sighted in California in 2008 migrated from Idaho [109]. Thus, it is likely a transient individual rather than from a naturalized California population. The status of other populations within the United States are either imperiled or presumed extirpated [5,83]. NatureServe provides a distributional map of wolverine.

The species has a circumpolar distribution, corresponding with the Boreal zone of the northern hemisphere (Kvam et al. 1988). The range of the wolverine reaches from Scandinavia through the Russian Federation and Siberia to Alaska, Canada and the western lower states of the United States south to California. The range includes territory of the following countries: Canada, China (Heilongiang, Xinjiang, Inner Mongolia), Estonia, Finland, Mongolia, Norway, Russian Federation, Sweden, and United States (Alaska, Wyoming, Idaho, Montana, Washington, Oregon and California) (Whitman 1999).

During the 19th century, wolverines disappeared from the southernmost of these areas in Europe mainly due to persecution, but also due to deforestation and other human developments. In Europe the species is now found in Norway, Sweden, Finland and European part of Russia. Within these countries wolverines are mainly found north of 60ºN. Based on geographic connectivity and genetic surveys the wolverines in Europe likely consist of five populations/occurrences.

Wolverines are found in North America and northern Eurasia, in the boreal zone of the northern hemisphere. They require large expanses of relatively undisturbed, boreal habitat. Wolverines are found in Scandinavia and Russia to 50 degrees North latitude. In North America they are found in Alaska and northern Canada, but can also be found in mountainous regions along the Pacific Coast as far south as the Sierras of California. Historically, wolverines were found in more southerly areas of Europe and North America, but these populations were extirpated mainly due to hunting, clearing of forests, and other human activities. Their distribution once extended as far south as Colorado, Indiana, and Pennsylvania in North America.

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

Other Geographic Terms: holarctic

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) 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]

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

Wolverines have a circumpolar distribution in the northern hemisphere, and are found from the western United States, Canada, and Alaska to Siberia, Russia, Eastern Europe and Scandinavia (3). Previously their distribution extended further south reaching the Baltic States and southern California respectively, but with human encroachment the range has retreated northwards, leaving remnant populations in pockets of remaining wilderness in sub-arctic regions (3). Populations in North America and Europe are sometimes divided into separate subspecies, known as Gulo gulo luscus and G. g. gulo, respectively (5).

Wolverines are one of the largest members of the family Mustelidae and are unmistakable in appearance. They are terrestrial mammals with body lengths of 65 to 105 cm, tail lengths of 13 to 26 cm, and shoulder heights of 36 to 45 cm. Wolverines weigh from 9 to 30 kg, females are generally smaller than males by about 10% in linear measurements and 30% in weight. They have short, powerful limbs and 5 toes on each paw. They use a semi-plantigrade form of locomotion, with their weight primarily on their metatarsals. This distributes weight better and can be useful when traveling and hunting in snow. On hard ground, ungulates can outrun wolverines. In snow, wolverines are less likely to sink in and can often catch much larger animals that become immobilized in deep snow. Wolverine fur is usually brown or brownish-black, with a yellow or gold stripe extending from the crown of the head laterally across each shoulder and to the rump, where the stripes join at the tail. Wolverines have a stocky appearance, with a robust body, short, powerful limbs, a large head, and small, rounded ears. They have sharp claws that are semi-retractable and a very powerful bite, with which they crush bone. They are rarely seen by humans because of their low population densities and the remote terrain in which they live.

There are two subspecies of wolverines: North American wolverines (G. gulo luscus) and European wolverines (G. gulo gulo). Differences seem to be mainly genetic and probably as a result of the isolation of these two continental populations. Another possible subspecies on Vancouver Island, Canada: G. gulo vancouverensis. This population has skull morphology differences with those found on the mainland, but their status has yet to be decided.

Range mass: 9 to 30 kg.

Range length: 65 to 105 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Average basal metabolic rate: 31.765 W.

Sexual Dimorphism: Males are 25%-30% heavier than females.

Length:
Range: 650-1,050 mm

Weight:
Range: "12.7-14.1 kg males; 8.3-9.9 kg females "

Length: 100 cm

Weight: 15000 grams

Differs from the fisher in having yellowish stripes on the sides. Differs from the badger in having darker overall coloration (badger is yellowish gray), yellowish lateral stripes, and longer limbs; lacks the white stripe that in the badger extends from the snout over the top of the head to at least the neck.

Elevational and vegetation use varies by season [115]. In Norway, wolverines selected habitats at significantly higher elevations in summer than in winter (P<0.001) [65]. Average elevations used by wolverines in northwestern Montana are 4,500 feet (1,371 m) in winter, 5,500 feet (1,676 m) in spring, 6,300 feet (1,920 m) in summer and 6,200 feet (1,889 m) in fall [54]. Winter populations in Idaho ranged from 5,800 to 7,800 feet (1,800-2,400 m) [7]. In southern Alaska, wolverines are widespread above and below treeline [101]. Wolverine tracks in British Columbia and Alberta were found only in upland habitats [123]. Significantly (P<0.05) higher elevations were used during winter (3,130 feet (954 m)) than in summer (2,870 feet (874 m)) in Alaska [115]. On average, wolverines were found at 2,000 to 3,900 feet (600-1,200 m) [116], with a range of 1,000 to 5,900 feet (300-1,800 m) [42,115,116]. Elevations of 4,000 to 5,000 feet (1,219-1,523 m) were significantly avoided (P<0.05) in Alaska [115]. Movements to lower elevations during winter in Idaho may be correlated to an increase in carrion abundance attributed to big game hunting seasons [31].

More info for the terms: climax, cover, selection, shrub, tundra

In general, wolverines prefer high-elevation habitats in summer and low-elevation habitats in winter [46,115]. Selection may be influenced by seasonal variation in prey selection or abundance, human disturbance, or denning requirements [31,61]. Habitat use for males in winter was negatively associated with helicopter skiing. Females were negatively associated with helicopter and backcountry skiing in winter. Overall, wolverines appear to avoid areas that are heavily utilized by people [61].

• Winter: Suitable winter range appears to overlap with forested areas and deep spring snow cover [5,32]. Forested, birch-willow-alder (Betula spp.-Salix spp.-Alnus spp.), and rock-ice habitat types are used in south-central Alaska [116]. In Idaho, low-elevation Douglas-fir and lodgepole pine habitats are utilized [32]. Wolverines in Sweden spent their time on low mountains or in coniferous forests bordering high mountains [46]. Lowland coniferous forests are utilized in British Columbia [36]. In mid-winter, wolverines in British Columbia and Alberta appear to prefer dense climax forest with lower snow depth over stands with high snow depth [122]. Montane coniferous forests in Idaho were preferred over other habitat types, but the difference was not significant (P>0.05). Rock habitats were avoided during winter in Idaho [31]. Wolverines in Idaho were associated with streams in winter, possibly because they provided travel corridors at that time of year, which were unnecessary in summer [32]. At least one wolverine in Idaho may have been following elk downstream [7]. The habitats preferred by females in the Yukon Territory were alpine talus, subalpine conifer, and boreal conifer [10]. Wolverines traveled in areas with significantly lower snow depth than random areas (P<0.01) [122].

• Summer: In general, wolverines use more open areas in summer than in winter. In summer, wolverines in Idaho utilized high-elevation whitebark pine habitat [32] and showed a significant preference (P<0.05) for rock cover [31]. In south-central Alaska, tundra, birch-willow-alder, and rock-ice habitat types are utilized [116]. In the Yukon Territory, the most preferred habitats were alpine shrub, subalpine shrub, subalpine grass, subalpine conifer, and boreal conifer forest [10]. Females were positively associated with alpine and avalanche habitats with abundant hoary marmots (Marmota caligata) and Columbia ground squirrels (Spermophilus columbianus) [61]. In British Columbia, wolverines occupy alpine meadows [36]. Females avoided roads and recently logged areas in British Columbia [61].

More info for the terms: cover, density, presence, shrub, tundra

Wolverines appear to have few specific habitat requirements aside from extensive wilderness dominated by coniferous forest of sufficient size to support wide-ranging, solitary individuals [2,30,104]. In the continental United States, wolverines are primarily found in stands dominated by fir (Abies spp.), spruce (Picea spp.), hemlock (Tsuga spp.), Douglas-fir, or lodgepole pine [41,54,55]. In Oregon, source habitats include alpine tundra and all subalpine and montane forests. Within these habitats, all structural stages except the stem exclusion stage act as source habitats [119].

Wolverines are positively associated with snags, downed logs, large hollow trees, talus [29,120], remote undisturbed wilderness or wilderness with minimal motorized access [29,54], numerous denning sites, and abundant prey [29]. Denning sites may be a critical and limiting resource in wolverine habitats [31]. Other habitat attributes for wolverines in the northern Rocky Mountains and southwestern Canada include significant (P≤0.05) preferences for high elevations, topographic complexity, high annual snowfall, cirque denning habitat, and low human population density. A distribution model indicates a positive relationship with snowfall, cirque habitat, and forest edge, suggesting that alpine and subalpine habitats are important for the wolverine. Another interpretation for the model suggests that wolverines are limited to regions of low human activity rather than by vegetation structure and type [26]. Road densities of ≤0.44 km/km² were most likely to benefit wolverines in the interior Pacific Northwest, according to another habitat model. In the same model, low human population density was also a reliable predictor of wolverine presence [94].

Numerous forest cover types and open habitats are utilized by wolverines. Individuals in Idaho traveled through cover types ranging from dense timber to open ridgetops. Specific examples include low-elevation forested drainages to high-elevation cirque basins with low overstory cover [30]. A wolverine in British Columbia or Alberta traveled through a burned upland area dominated by second-growth lodgepole pine, which formed a low dense canopy [122]. Dense, homogenous black spruce stands in British Columbia and Alberta were used for traveling [123]. Summer and winter habitat use for males in British Columbia was positively correlated with moose winter range, bottomland forests, and avalanche chutes [61]. In northwestern Montana, 70% of all radio-collared wolverine relocations were in large areas of low- to medium-density, mature forest habitat. The other 30% of relocation sites were in ecotonal areas, small forested pockets, or rocky forested benches. Wet and dry forest were used 23% and 31% of the time, respectively. Alpine areas were utilized 16% of the time. On rare occasions, wolverines were relocated in burned or wet meadow areas. Dense, young forest was used less than all other habitat types [54]. Preferred habitats in the Yukon Territory were subalpine coniferous forest, boreal coniferous forest, and subalpine shrub. Other habitats favored by females include alpine shrub, subalpine mixed forest, and boreal mixed forest [10]. Males showed a strong preference for subalpine coniferous forest and subalpine shrubland in the Yukon Territory [10,12]. Riparian habitat was utilized in proportion to its availability in the Yukon Territory [12]. In south-central Alaska, use of tundra was lower than expected in winter, and use of forests was lower in summer [116].

Preferences for other habitat attributes are highly variable. Preferences for cover, aspect, slope, and elevation varied widely by individual in the Yukon Territory [10,12]. Northerly aspects were used significantly more (P<0.05) than other aspects in Idaho [31,32]. In northwestern Montana, basins, eastern and southern aspects, and edge habitats were preferred. Slopes were used 36%, basins 22%, wide river bottoms 14%, and ridge tops 8% of the time [54].

Wolverines crossed clear-cuts and recent burns in northwestern Montana but appeared to move through them quickly. Wolverines were located within 0.6 to 1.7 miles (1-3 km) of clear-cuts and active roads 12 times during the northwestern Montana study [54]. Roads, which were generally in low-lying areas, were avoided in Idaho. Wolverines were not associated with maintained trail systems or elk winter range [32].

Habitat and Ecology

Systems

• Terrestrial

Wolverines are found in alpine forests, tundra, open grasslands, and boreal shrub transition zones at or above timberline. Generally they live in areas with low human development and need large, undisturbed ranges in order to survive. During the winter, females construct nests to store food and hide young. They construct rough beds of grass or leaves in caves or rock crevices, in burrows made by other animals, or under a fallen tree. They occasionally construct their nests under the snow. Wolverines are found exclusively in areas with cold climates, which may be related to their reliance on scavenging and caching large animal prey. Cold weather helps preserve the meat for later use.

Habitat Regions: temperate ; polar ; terrestrial

Terrestrial Biomes: tundra ; taiga ; forest ; mountains

Comments: Alpine and arctic tundra, boreal and mountain forests (primarily coniferous). Limited to mountains in the south, especially large wilderness areas. Usually in areas with snow on the ground in winter. Riparian areas may be important winter habitat. May disperse through atypical habitat. When inactive, occupies den in cave, rock crevice, under fallen tree, in thicket, or similar site. Terrestrial and may climb trees.

Young are born in a den among rocks or tree roots, in hollow log, under fallen tree, or in dense vegetation, including sites under snow.

Found in alpine, tundra and northern taiga habitats (4).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

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.

Tends to occupy higher elevations in summer, lower elevations in winter (Hornocker and Hash 1981, Whitman et al. 1986).

Male home ranges large: up to 1,000 square kilometers (RIC 1999); averaging 422 square kilometers in Montana (Hornocker and Hash 1981) and 535 square kilometers in Alaska (Whitman et al. 1986). Home ranges of females with young much smaller, ranging from 73 to 416 square kilometers (Hornocker and Hash 1981, Gardner 1985, Magoun 1985, Whitman et al. 1986, Banci 1987, Copeland 1996).

The wolverine diet can include anything from small eggs to large ungulates. They are capable of bringing down prey that is five times bigger than themselves, but generally only under conditions that leave large ungulate prey stranded in deep snow. They have large claws with pads on the feet that allow them to chase down prey in deep snow. Large ungulate prey species include reindeer, roe deer, wild sheep, elk or red deer, maral and moose. Wolverines can be very swift when on the attack, reaching speeds of over 48 km an hour. Large prey are killed by biting the back or front of the neck, severing neck tendons or crushing the trachea. Wolverines are opportunistic and their diet vary with season and location. They are also specialized for scavenging and will readily take over carcasses that have been killed by other large predators. Wolverines are extremely strong and aggressive for their size, they have been reported to drive bears, cougars, and even packs of wolves from their kills in order to take the carcass. They have also been reported scavenging whale, walrus, and seal carcasses. Female wolverines may hunt more small to medium-sized animals such as rabbits and hares, ground squirrels, marmots, and lemmings, when they are rearing young. The amount of food available to females may be key in determining population size; more food leads to greater reproductive success. The scientific name Gulo gulo comes from the latin word for glutton. Like other mustelids, they can be somewhat driven to kill when given the opportunity, resulting in them killing more prey than they can eat or cache. Wolverines have been known to kill large numbers of captive reindeer in deep snow, simply because the reindeer cannot escape.

Animal Foods: birds; mammals; eggs; carrion

Foraging Behavior: stores or caches food

Primary Diet: carnivore (Eats terrestrial vertebrates, Scavenger ); omnivore

Comments: Opportunistic. Feeds on a wide variety of roots, berries, small mammmals, birds' eggs and young, fledglings, and fish (Hatler 1989). May attack moose, caribou, and deer hampered by deep snow. Small and medium size rodents and carrion (especially ungulate carcasses) often make up a large percentage of the diet. Prey are captured by pursuit, ambush, digging out dens (Biosystems Analysis 1989), or climbing into trees. May cache prey in fork of tree branches or under snow.

Wolverines are scavengers, using the kills of larger predators, such as bear and wolves. Wolverines have few (if any) natural predators, and prey on large game and smaller animals. Wolverines are reliant on other large predators for food when snow conditions don't make it possible for them to hunt large prey themselves. The presence of wolverine urine discourages presence and feeding of black-tailed deer (Odocoileus hemionus columbianus) and snowshoe hares (Lepus americanus). Wolverines are parasitized by many kinds of endo and ectoparasites, including flukes (Opisthorchis felineus), tapeworms (Bothriocephalus, Taenia twitchelli, Mesocestoides kirbyi), roundworms (Dioctophyme renale, Soboliphyme baturini), trematodes (Alaria), nematodes (Trichinella spiralis, Molineus patens, Ascaris devosi, Physaloptera torquata, Physaloptera sibrica), ticks (Dermacentor variabilis), fleas (Oropsylla alaskensis, and ear canker mites (Otodectes cynotis).

Commensal/Parasitic Species:

• flukes (Opisthorchis felineus)
• tapeworms (Bothriocephalus)
• tapeworms (Taenia twitchelli)
• tapeworms (Mesocestoides kirbyi)
• roundworms (Dioctophyme renale)
• roundworms (Soboliphyme baturini)
• trematodes (Alaria)
• nematodes (Trichinella spiralis)
• nematodes (Molineus patens)
• nematodes (Ascaris devosi)
• nematodes (Physaloptera torquata)
• nematodes (Physaloptera sibrica)
• ticks (Dermacentor variabilis)
• fleas (Oropsylla alaskensis)
• ear canker mites (Otodectes cynotis)

Wolverines have few, if any, natural predators. They are fierce and aggressive, able to defend themselves against animals several times their size, such as wolves and mountain lions. However, wolves, mountain lions, black bears, brown bears, and golden eagles can be threats to young or inexperienced wolverines. Wolves are the dominant predator of wolverines, but generally only under circumstances where the wolverine cannot escape by climbing a tree. Wolverines use scents from their anal gland and urine to scent-mark food caches, discouraging other predators.

Known Predators:

• wolves (Canis lupus)
• mountain lions (Puma concolor)
• black bears (Ursus americanus)
• brown bears (Ursus arctos)
• golden eagles (Aquila chrysaetos)

Gulo gulo preys on:
Geomyidae
Marmota
Cervus elaphus
Odocoileus hemionus
Ovis canadensis
Arvicolinae
Spermophilus
Marmota broweri
Castor canadensis

Based on studies in:
USA: Montana (Tundra)

This list may not be complete but is based on published studies.

More info for the term: density

Wolverine densities are typically very low. An average density of 1 wolverine/65 km² was recorded for northwestern Montana [54]. Density estimates in Alaska ranged from 1 wolverine/48 km² to 1 wolverine/193 km² [17,75]. In the Yukon Territory estimates ranged from 1 individual/37 km² to 1 individual/778 km² [10,12]. Wolverine density in the Northwest Territories was estimated at 1 wolverine/136 km² to 1 wolverine/226 km² [69]. In British Columbia, wolverine density in high-quality habitats averaged 1 individual/161 km², in moderate-quality habitats 1 individual/244 km², and in low-quality habitats 1 individual/500 km² [73].

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: Unknown

Comments: 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.

10,000 to >1,000,000 individuals

Comments: Total population size is unknown but probably is at least in the hundreds of thousands. Substantial populations occur in northern Canada and Alaska. Estimates reported in 2003 put the total population in western Canada at 15,000-19,000 individuals (Environment Canada, Species at Risk website).

Outside of Alaska, Montana and Idaho likely have the largest populations in the United States (perhaps a few hundred individuals in each state). Acknowledging a lack of substantial data, Predator Conservation alliance (2001) stated that extrapolation of the best available information indicates an estimated population of fewer than 750 wolverines in the contiguous United States, including an estimated 400-600 in the U.S. northern Rocky Mountains, and perhaps 100 across the Northwest and Sierra Nevada.

In North America, population density estimates range from one wolverine per 65 sq km in Montana (Hornocker and Hash 1981) to less than one per 200 sq km in northern British Columbia (Quick 1953), Alaska (Becker and Gardner 1992), and the Northwest Territories (Lee and Niptanatiak 1993). [from Petersen 1997]

In Eurasia, data on current populations are scarce. In Norway, the population was estimated to be 120 to 180 individuals (Kvam et al. 1988), in Sweden less than 100 individuals (Andersson 1995, cited by Blomqvist 1995), and in Finland approximately 90 individuals (Nyholm 1993, cited by Blomqvist 1995). In the conservation parks of Russia, the average number of encounters with wolverine tracks along 10 km transects ranged from 0.03 to 1.8 (Russian Research Center 1992). [from Petersen 1997]

More info for the term: presence

Wolverines are capable of traveling long distances within short periods of time. In California, wolverines traveled 15 miles (24 km) or more per day searching for food [16]. Males easily travel over 19 miles (30 km) in a day [31,46,64,75,90]. Daily movements for males were significantly greater (P=0.041) than for females in Idaho [31]. A young male in the Greater Yellowstone Ecosystem traveled an average minimum distance of 12.9 miles (20.8 km) per day over a 42 day period from late March to early May [56]. Maximum daily distances traveled by males in the Yukon Territory were 10.7 miles (17.3 km). Estimated maximum daily distance traveled by females in the Yukon Territory was 7.0 miles (11.3 km) [10]. Daily movements for females in Idaho ranged 0 to 12.3 miles (19.8 km) [31]. Males moved a straight line average of 7.6 miles (12.3 km) per day during summer in northwestern Alaska. The greatest straight line distance covered by females in a single day was 9.7 miles (15.6 km). Males in northwestern Alaska moved up to 6.6 miles (10.6 km) per hour, while females moved up to 5.0 miles (8.0 km) per hour [75]. A young male in the Greater Yellowstone Ecosystem traveled 8.6 miles (13.8 km) in a 2-hour period [56].

Wolverines tend to utilize areas that make traveling easy. Wolverines generally travel along forested ridges and creek bottoms in Oregon [55]. Winter travel for wolverines in British Columbia and Alberta was limited to upland boreal forest [122]. Wolverines utilize trails created by skiers and snowshoers, which make travel easier in deep snow [6]. In Idaho, they commonly travel downstream along small streams in winter. They also travel through riparian areas, meadows and timber stands [7]. Wolverines are adept swimmers [64,93]. Thus, lakes and rivers most likely do not impede movements.

Temporary, long-distance, seasonal movements are common for males and females [12,54,75]. The reason for these extensive movements is largely unknown. These sudden increases in movement may be a response to the presence of other individuals in breeding condition moving into the same area. Another possible explanation is adjacent residents may attempt to occupy a vacated home range following the death or departure of the resident wolverine [75]. Movements in northwestern Montana were most extensive in spring and lowest in winter [54].

Movements by both females and males decline during the breeding season. Movements by males were influenced by breeding behavior from late winter to summer in northwestern Alaska. Raising young restricted the movements of adult females in northwestern Alaska [75].

Both male and female juveniles disperse [75], although some female kits remain in their mothers' home ranges [75,112]. Typically, all males disperse in Scandinavian populations [112]. Juveniles and transient subadults may disperse 19 to 235 miles (30-378 km) from their natal range [39,75,112]. A 2-year-old male traveled 235 miles (378 km) from Alaska (starting late March to mid-April) to the Yukon Territory (late November) [40]. A young tagged female believed to be from northwestern Alaska was trapped 186 miles (300 km) outside the original study area. The identity of the young female could not be verified [75].

More info for the terms: litter, monoestrous, parturition, polygamous

Wolverines are sexually dimorphic. Adult males average 24 to 61 pounds (10.9-27.5 kg), while adult females average 15 to 41 pounds (7-19 kg) [50,64,69,75,91]. The skull and teeth of wolverines are more robust than those of other carnivores of similar size. Wolverines are capable of eating frozen meat and crushing bones of large prey including deer (Odocoileus spp.), caribou (Rangifer tarandus), and moose (Alces alces) ([46], reviews by [50,85]).

Wolverines are solitary [85]. While they are primarily nocturnal [46,55], they also travel during daylight hours [7,46]. Wolverines are active year round [10,54,64,75,115]. Rather than maintaining territories, wolverines scent mark to advertise their current positions [54]. Individual home ranges may overlap extensively with those of other individuals [10,54].

Males and females reach sexual maturity at 2 to 3 years of age [10,13,91]. Some males reach sexual maturity at 14 to 15 months of age [91]. Occasionally, females produce litters as yearlings [10,13,91]. Most females produce litters every 2 to 3 years [31,54,64]. Physical condition and age may be a factor in whether females reproduce each year [31,87].

Rausch and Pearson [91] speculated that wolverines are polygamous. Observations of the breeding biology of wolverines suggest that females are monoestrous [13,90,91]. The mating season spans April to August, with a peak in late May and June [64,91]. Male breeding condition peaks April to June. Delayed implantation typically occurs in late January or early February [91,124], but may happen anytime from November through March [10,13,91].

Parturition (births) occurred 215 to 272 days after copulation in captive wolverines [81]. Active gestation lasts 30 to 40 days [91]. Births peak February to March [46,77,85,90,91], but may occur at any time from January through April [31,75,90,91]. Wolverine parturition may correspond with periods when carrion is most abundant [91], such as caribou calving season [29].

Litter sizes range from 1 to 6 kits per litter, with an average of 2.2 to 3.0 kits per litter [46,54,90]. Average litter size for females in northwestern Alaska was 1.75 kits after dens were abandoned. This did not include newborn mortality [75].

Kits are weaned by 10 weeks of age [31,64] and remain with their mothers up to 2 years [64,112]. The average dispersal age for males and females in Scandinavia was 13 months [112].

According to a review, average annual survival may range from 0.80 to 0.975 [11]. More recent studies have recorded survival rates that deviate slightly from the range. Average first-year survival for juveniles in Scandinavia was 0.68 [88]. Average annual survival in Idaho and Montana was 0.80 excluding licensed trapping, and 0.57 including licensed trapping [105]. In a 12-study synthesis, overall annual survival for all age and sex classes in untrapped populations was >0.84. Overall annual survival for all age and sex classes in trapped populations was <0.75 [62].

Average life expectancy of wild wolverines in Montana is 4 to 6 years, with few exceeding 8 years of age according to unpublished data by Hash [50]. According to a review, wild wolverines may reach 8 to 10 years old [57]. The oldest wolverine examined by Rausch and Pearson [91] in Alaska and the Yukon Territory was a 13-year-old female.

Home Range: Wolverine home ranges may overlap, and adults do not actively defend territories [10,54]. Home range overlap most often occurs between resident adults and related subadults [31]. Adult females exclude unrelated females from their home ranges but allow offspring to occupy the same area [75]. Males generally tolerate females and juvenile males [31,75] but exclude other adult males from their home ranges [64,75,115]. Home ranges of juveniles and transient adult males may overlap the home ranges of resident males for unknown periods of time. When one male is in the overlapping area, the other male is typically not in the near vicinity [39].

Wolverine home range size can vary widely. The variation may be associated with differences in the abundance or distribution of food ([31], review by [11]). The average annual home ranges for adult males and males of unknown age are 139 to 257 mi² (359-666 km²) [54,75,115]. The average annual home range for female wolverines is 150 mi² (388 km²) in Montana [54]. Annual home ranges for females in Alaska averaged 40 to 41 mi² (103-105 km²) [75,115]. Average summer home range for females in northwestern Alaska was 36 mi² (94 km²). Average summer home range for adult males in northwestern Alaska was 242 mi² (626 km²) [75].

Many wolverines make temporary long-distance excursions [12,54,75]. These excursions can skew home range estimates. As a result, several methods have been developed to estimate the size of the areas primarily used by wolverines. Copeland [31] estimated harmonic mean core home ranges for wolverines in Idaho. Harmonic mean core home range is the area within the home range that is used more than expected based on an assumption of uniform usage [31,96]. Rather than determine the size of the area with the highest concentration of use for wolverines in the Yukon Territory, Banci and Harestad [10,12] estimated a core home range based on the size of the area that circumscribed 90% of the relocations of radio-collared wolverines.

Home ranges for wolverines in Idaho were larger than for other populations in North America. The following home range results from Idaho are based on annual estimates. Average home range for adult females was 148 mi² (384 km²), while the average harmonic mean core home range for adult females was 98 mi² (254 km²) [31]. For subadult females in Idaho, the average home range was 205 mi² (532 km²), with an average harmonic mean core home range of 88 mi² (227 km²). For adult males, average home range was 588 mi² (1,522 km²), and the average harmonic mean core home range for adult males in Idaho was 314 mi² (813 km²). Average home range for subadult males was 426 mi² (1,104 km²), while the average harmonic mean core home range for subadult males in Idaho was 201 mi² (520 km²) [31].

Reproductive activities may also influence wolverine home range size. Spring and summer home ranges tend to be larger for females without young than for females with kits [10,75]. A denning female captured several times from November to January in the Yukon Territory had a 5.4 mi² (14 km²) home range and relied heavily on baited traps [12]. The average March to August home range for lactating females in northwestern Alaska was 27 mi² (70 km²). Adult females without young had an average home range of 37 mi² (97 km²) March to August [75]. Core home ranges in the Yukon Territory were 18 mi² (47 km²) for a female with kits, and 52 mi² (134 km²) and 49 mi² (128 km²) for 2 females without young [10]. Similarly, home range estimates from the Yukon Territory that excluded temporary long-distance movements were 29 mi² (76 km²) (female with kits) and 59 to 61 mi² (153-157 km²) (females without kits) [12]. By comparison, core home ranges in the Yukon Territory were 109 mi² (283 km²) for a subadult male and 73 mi² (188 km²) for an adult male [10].

Total home range size estimates for wolverines in North America Age/Gender Annual home range (km²)* Spring/Summer home range
(km²)* Adult or unknown aged male 238-2,400 46-898 [10,12,16,31,54,69,75,115] Juvenile/subadult male 46-2,940 41-437 [10,31,75] Adult or unknown aged female (reproductive status unknown) 53-637 38-515 [10,16,31,54,75,115] Female with young 139 55-293 [10,31,54,75] Female (postpartum) 72-137 ...** [115] Female without young 202-343 68-210 [10,12,75] Juvenile/subadult female 370-646 ... [31] *Estimated minimum and maximum limits of annual and seasonal home range.
**No data.

Solitary and wide ranging. Occurs at relatively low population densities (e.g., 1 per 65 sq km in one area in Montana).

Males in some areas apparently are territorial, but in Montana there was extensive overlap of the ranges of both the same and opposite sexes. Apparently territory/range size depends on availability of denning sites and food supply (see Wilson 1982). Some individuals travel regularly over the same route (Wilson 1982).

There are no important predators other than humans. See Whitman et al. (1986).

Like most mustelids, wolverines have anal scent glands which are used to mark territories and food caches. Due to their scavenging lifestyle, they have an advanced sense of smell. Wolverines also have good hearing, but likely have poor vision. Wolverines are rarely vocal, except for occasional grunts and growls when irritated.

Communication Channels: acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Comments: Active throughout the year. Active both day and night but primarily nocturnal.

In the wild, wolverines generally live for 5 to 7 years but some can live up to 13 years. Females in captivity have bred up to 10 years old and live up to 17 years. The main causes of death are starvation, being killed by competitors (such as wolves), and trapping.

Range lifespan
Status: wild: 13 (high) years.

Range lifespan
Status: captivity: 17 (high) years.

Typical lifespan
Status: wild: 5 to 7 years.

Average lifespan
Status: captivity: 18.0 years.

Average lifespan
Status: captivity: 17.3 years.

Maximum longevity: 19.5 years (captivity) Observations: These animals feature delayed implantation (Ronald Nowak 1999). Depending on how long the implantation takes to occur, the total gestation time can take from 120 to 272 days, even though the active developmental time is about 35 days (Virginia Hayssen et al. 1993).

Wolverines are generally solitary animals. Males and females come together only briefly for mating, from May to August. Males have large home ranges, encompassing the home ranges of several females. Males may mate with each female in their home range and sometimes those in overlapping ranges. Males and females remain together for several days. Females may also mate with members of different home ranges, but litters are usually fathered by one male. Males fiercely defend their territory by marking it with scent from their anal gland.

Mating System: polygynous

Female wolverines mate every other year. Mating occurs from May to August, with most females being in heat from June to August. Males remain near females during the breeding season, but females initiate copulation. Like many other mustelids, ovulation is believed to be induced by copulation and the embryo is not implanted immediately, but rather waits in diapause for about 6 months. After implantation, gestation takes only another 30 to 50 days. With delayed implantation, pregnancy can last from 120 to 272 days depending on when the embryo is fertilized and when it implants. Females build snow-dens in which they give birth and nurse. The litter is usually born between January and April and averages 3 kits, weighing 85 g each. Weaning is complete at 3 months and the young begin foraging on their own at 5 to 7 months, when they become independent. Adult size is attained at around 1 year and sexual maturity at 2 to 3 years old. Wolverines require snow cover that persists through spring so that food can be cached until the kits are large enough to being foraging on their own.

Breeding interval: Females give birth in alternate years.

Breeding season: Breeding occurs from May to August.

Range number of offspring: 1 to 5.

Range gestation period: 120 to 272 days.

Average birth mass: 84 g.

Average weaning age: 3 months.

Average time to independence: 1 years.

Average age at sexual or reproductive maturity (female): 710 days.

Average age at sexual or reproductive maturity (male): 776 days.

Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; delayed implantation

Average birth mass: 95 g.

Average number of offspring: 3.

Average age at sexual or reproductive maturity (male)
Sex: male: 776 days.

Average age at sexual or reproductive maturity (female)
Sex: female: 710 days.

Females give birth to a litter of around 3 kits in a snow den. After females give birth they hide with their young. The mother defends her territory and intruders are not tolerated. This territorial behavior continues until the young are ready to hunt on their own. Young remain with their mother until the fall of the year they were born, when they disperse. Females mate again in the following year, giving birth to young in the second year after the previous litter. Females may help to train their young in hunting techniques before they disperse.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)

Breeds April-October (but variable), usually in summer. Implantation is delayed generally until winter. Gestation lasts 7-9 months; active gestation 30-40 days. One to six (usually 2-4) young are born January-April, mainly February or March (reportedly April-June in the Pacific states, Ingles 1965). Young are weaned beginning at about 7-8 weeks, separate from the mother in the fall. Sexually mature generally in the second or third year. Males sexually mature sometimes as yearlings (Alaska and Yukon); males over three years old were sexually mature in British Columbia. Some females mature at 12-15 months and produce their first litter when two years old. (Wilson 1982). In some areas, females may produce litters only every 2-3 years. In British Columbia, most mature females were reproductively active. Lives to an age of up to about 10 years, or sometimes 15-18 years or so.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 8 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 11
Species With Barcodes: 1

Proposed Threatened [110]

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Near Threatened
  (IUCN 2008)
• 1996
  Vulnerable
  (Baillie and Groombridge 1996)
• 1994
  Vulnerable
  (Groombridge 1994)
• 1990
  Vulnerable
  (IUCN 1990)
• 1988
  Vulnerable
  (IUCN Conservation Monitoring Centre 1988)

Wolverines generally occur at relatively low population densities and have vanished from most of their former range in the United States. In Scandinavia, estimates vary from one individual per 200 to 500 sq km. Encroaching human populations alter the abundance and habits of large ungulates, eliminate large predator populations, or kill wolverines directly. Numbers have declined due to fur trapping and hunting by those believing the wolverine to be a nuisance. In Russia, wolverines are a game species and extensive overhunting has led to population decline. In the United States, wolverines can only be harvested in Montana and Alaska. Wolverines have been nearly eliminated in the United States and have disappeared over most of southeastern and south-central Canada. In Europe, they can only be found now in parts of Scandinavia and northern Russia. Wolverines are listen by the IUCN as Near Threatened. They were previously listed as vulnerable, but have been upgraded to Near Threatened.  Conservation efforts include education, protecting habitat, and eliminating unregulated hunting. In Sweden farmers and herders are compensated for identifying dens and reporting them. Other Scandinavian countries have adopted measures to limit the amount of wolverines in reindeer herding areas through selected hunting.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N3 - Vulnerable

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: 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.

Intrinsic Vulnerability: Highly vulnerable

Comments: Species has a low reproductive output because of poor breeding success, high juvenile mortality, and slow sexual maturity (Petersen 1997).

Vulnerable.

Classified as Near Threatened (NT) on the IUCN Red List (1).

Population

Population Trend

Global Short Term Trend: Relatively stable to decline of 30%

Comments: Environment Canada - Species at Risk website (http://www.speciesatrisk.gc.ca ) reported the following information for the western population:

In the Yukon, populations are healthy and stable in all regions. In the Northwest Territories, densities vary with location; they are highest in the southwest and lowest on the Arctic Islands and on the mainland east of the Thelon Wildlife Sanctuary. In Nunavut, densities are moderate in the west and low on the Arctic Islands and in the east. Populations are believed to be stable over much of British Columbia, but are declining in the southern mountains. A distinct subspecies may no longer be extant on Vancouver Island, where Wolverines have not been seen since 1992; their decline may be related to that of the endangered Vancouver Island marmot, a potential summer food. In Alberta, wolverines are most abundant in the west, but appear to be declining throughout the province. In Saskatchewan, they are common in the north, but are rare and possibly declining in the southern boreal forest. In Manitoba, the highest densities are in the northeast and northwest, while numbers in the north central part of the province are unknown. Wolverines are found in small numbers in northwestern Ontario; they may have increased recently in some areas, but are known to have disappeared from others. Overall numbers for Ontario indicate a decline. Although records exist for their occurrence in the Prairie and Great Lakes Plains ecological areas, wolverine populations may never have been viable in these regions.

See also Dauphine (1989 COSEWIC report) for information on status in Canada.

In Alberta, trapping data suggest that the highest populations are found in the western parts of the province, and that populations have declined in most regions of Alberta in the past two decades (Petersen 1997).

Degree of Threat: High

Comments: 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).

The most common causes of wolverine mortality outlined in a 12-study synthesis were hunting or trapping, starvation, and predation [62]. Overtrapping and habitat loss are the largest threats facing the wolverine [54,108]. Wolverines are highly attracted to traps baited with carrion as well as those that have already trapped another animal [55]. Wolverines are considered a pest by trappers because they mutilate trapped furbearers and destroy traps [11,44,55]. Hunting and trapping may lead to local declines in wolverine populations. Surrounding wolverine populations may recolonize overhunted areas [33]. Many untrapped areas have wolverine populations with positive growth that can act as restocking refugia for neighboring populations experiencing negative growth [62]. Hornocker and Hash [54] concluded that protected wilderness areas along with limited hunting pressure would allow wolverines to persist in northwestern Montana. Thus, it may be possible to establish a balance between maintaining stable wolverine populations and preserving local hunting and trapping traditions in some areas.

Other human activities, such as agriculture, development, and eradication campaigns against other predators, have negative indirect effects on wolverine populations. Large scale poisoning of gray wolves in the 1970s had a negative impact on wolverines in Canada because wolverines rely on carrion from kills by gray wolves for survival [28]. Agriculture, silvicultural practices, and oil, gas, and mineral development can fragment habitats, which could have negative effects on wolverine populations [11]. Large hydroelectric reservoirs may threaten wolverine habitat and prey [115]. The effects of villages on wolverine populations in Alaska were unknown [75]. As stated in a review, populations are likely limited by clear-cut logging, road construction, and snowmobile and other off-road vehicle use that can disturb large wilderness areas [84]. Silvicultural practices that reduce the overstory would be detrimental to wolverine populations in winter [122]. Wolverines cross clear-cuts and burns in western Montana, but they appear to spend as little time within these areas as possible. Males in Montana are found further from active roads, clear-cuts, and burns than females [54].

Roads divide habitats and may impede wolverine movements, isolating populations. Wolverines along the British Columbia-Alberta border avoided areas <330 feet (100 m) off the Trans Canada Highway and showed a preference for areas >3,600 feet (1,100 m) off the highway. They also avoided sections of a ski trail that were within 660 feet (200 m) of the highway and preferred trails >3,600 feet (1,100 m) from the highway. Wolverines crossed the Trans Canada Highway 50% of the time when approached but only where the rights-of-way were shortest. Railway rights-of-way did not impede wolverine crossing when the railways were not associated with the Trans Canada Highway. Wolverines may be more vulnerable to traffic when road rights-of-way are wide. An ideal road design would be straight roads with rights-of-way <160 feet (50 m) [6].

Major Threats

Wolverines have declined through much of their historic range; they are very sensitive to human disturbance and have retreated to remaining areas of wilderness (4). They continue to be threatened by habitat loss and also by a loss of prey species or even other carnivores (such as wolves) that provide carrion (4). Where they do exist near humans they can come into conflict with farmers from attacking livestock; persecution and poaching are therefore pertinent threats (4). In addition, populations that are protected are slow to recover due to slow reproduction rates caused by the small litter size and the fact that females only reproduce every few years (4).

Conservation Actions

Preserve Selection and Design Considerations: Maintaining wilderness and roadless areas is critical. In timber harvest areas, roads should be minimized.

Although wolverines maintain large home ranges, they exhibit fidelity to discrete areas, and populations in scattered sites within areas such as the Northwest Territories (Canada) are genetically independent, suggesting the need to consider preservation of multiple populations if genetic diveristy is to be maintained (Wilson et al. 2000).

Management Requirements: Management programs must be regional, rather than local, for this wide-ranging, low-density species.

Rowland et al. (2003) evaluated performance of landscape models for wolverines within their historical range at 2 scales based on recent observations (n = 421) from Washington, Oregon, Idaho, and Montana. At the subbasin scale, simple overlays of habitat and road-density classes were effective in predicting observations of wolverines. At the watershed scale, they used a Bayesian belief network model to provide spatially explicit estimates of relative habitat capability. The model had 3 inputs: amount of habitat, human population density, and road density. At both scales, the best models revealed strong correspondence between means of predicted counts of wolverines and means of observed counts. Their results can be used to guide regional conservation planning for wolverines.

See Predator Conservation Alliance (2001) for a summary of management needs.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Protected legally in several western states. Occurs in several national parks.

Needs: Kyle and Strobeck (2002) confirmed that high levels of gene flow occur among all the northern wolverine populations sampled. They "also observed progressively increasing genetic structure at the periphery of their southern and eastern distributions, suggesting that these populations may have been partially fragmented from what was once a panmictic unit. Peripheral populations may be more susceptible to extirpation and, therefore, may be the most appropriate targets for concerted conservation efforts to prevent the elimination of wolverines from yet more of their historical range."

Protection of natal denning habitat from human disturbance may be critical. Montane coniferous forests, suitable for winter foraging and summer kit rearing, may only be useful if connected with subalpine cirque habitats required for natal denning, security areas, and summer foraging. In addition, these habitats must be available during the proper season. Subalpine cirque areas, important for natal denning, may be made unavailable by winter recreational activities. Conversely, high road densities, timber sales, or housing developments on the fringes of subalpine habitats may reduce potential for winter foraging and kit rearing, and increase the probability of human-caused wolverine mortality. [from www.wolverinefoundation.org].

See also Predator Conservation Alliance (2001) for a summary of protection needs.

Keep trappers out of known wolverine areas.

WWF International launched a Large Carnivore Initiative for Europe (LCIE) in 1995 and under this initiative an Action Plan has been drawn up for the conservation of this species in Europe (6). The wolverine is protected in much of its range but more research into the population dynamics and behaviour of this elusive creature are desperately needed. In Europe especially, where there are fewer areas of true wilderness left, any conservation initiative will have to work closely with local people to combat prejudice (4). In the United States, the wolverine is yet to be listed on the Endangered Species Act due to the paucity of data surrounding this species, highlighting once again the need for further research (3).

Wolverines live in remote areas where human populations are sparse. Many wolverines are shot due to their habit of preying upon animals that are trapped for fur. They have been extensively hunted in Scandinavia because of its alleged predation on domestic reindeer. It has been considered a nuisance throughout its range because it will eat animals already caught in fur traps and will break into cabins and food caches, eating and spraying the contents with its strong scent. Wolverines can even break into canned goods with their sharp canines. Wolverines are supposedly very difficult to trap; when a wolverine finds a trap, it may spring it by turning it upside down or by dropping a stick into it. Wolverines have also been known to carry traps away and bury them deep in the snow.

Negative Impacts: injures humans; crop pest

Wolverine are sometimes hunted for their fur because it is prized for its frost resistant properties. Native peoples used them to line parkas. However, their skins are no longer used widely in commerce. Wolverines are also important members of the ecosystems in which they live, they are important as top predators and scavengers.

Positive Impacts: body parts are source of valuable material

Comments: Fur is favorable for trimming parkas, but limited numbers make the wolverine relatively unimportant as a furbearer. In the 1970s, annual harvest was several hundred in Alaska and a few dozen in Montana (Wilson 1982). In the early 1980s, the harvest in Canada, Alaska, and Montana was 1377 (Nowak 1991).

Sometimes regarded as a nuisance; may rob traplines or destroy human food caches. Was intensively hunted in Scandinavia because of alleged predation on domestic reindeer (Nowak 1991).