Animal Diversity Web

Ge­o­graphic Range

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "United States Fish and Wildlife Ser­vice", 2008; Abramov and Wozen­craft, 2008; "Alaska Fish and Wildlife Ser­vice", 2007; "United States Fish and Wildlife Ser­vice", 2008; "Wolver­ine", 2009; Abramov and Wozen­craft, 2008; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Biogeographic Regions
• nearctic
  • native
• palearctic
  • native

• Other Geographic Terms
• holarctic

Habi­tat

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. ("En­cy­clo­pe­dia Bri­tan­nica", 2009; "The Wolver­ine Foun­da­tion", 2006; "United States Fish and Wildlife Ser­vice", 2008; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995; Roel, et al., 2006; Rug­giero, et al., 2007)

• Habitat Regions
• temperate
• polar
• terrestrial

• Terrestrial Biomes
• tundra
• taiga
• forest
• mountains

Phys­i­cal De­scrip­tion

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "En­cy­clo­pe­dia Bri­tan­nica", 2009; "The Wolver­ine Foun­da­tion", 2006; "United States Fish and Wildlife Ser­vice", 2008; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "The Wolver­ine Foun­da­tion", 2006; "United States Fish and Wildlife Ser­vice", 2008; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  9 to 30 kg

  19.82 to 66.08 lb

• Range length

  65 to 105 cm

  25.59 to 41.34 in

• Average basal metabolic rate

  31.765 W

  AnAge

Re­pro­duc­tion

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. ("Alaska Fish and Wildlife Ser­vice", 2007; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• 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. ("AnAge: The An­i­mal Aging and Longevity Data­base", 2005; "The Wolver­ine Foun­da­tion", 2006; "Wolver­ine", 2009; Abramov and Wozen­craft, 2008; Lofroth, et al., 2007; Nowak, 1999; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Key Reproductive Features
• iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous
• delayed implantation

• Breeding interval

  Females give birth in alternate years.

• Breeding season

  Breeding occurs from May to August.

• Range number of offspring

  1 to 5

• Average number of offspring

  3

  AnAge

• Range gestation period

  120 to 272 days

• 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 (female)
  Sex: female

  710 days

  AnAge

• Average age at sexual or reproductive maturity (male)

  776 days

• Average age at sexual or reproductive maturity (male)
  Sex: male

  776 days

  AnAge

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "AnAge: The An­i­mal Aging and Longevity Data­base", 2005; "En­cy­clo­pe­dia Bri­tan­nica", 2009; "Wolver­ine", 2009; Copeland, 1996; Lofroth, et al., 2007; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• 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

Lifes­pan/Longevity

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "AnAge: The An­i­mal Aging and Longevity Data­base", 2005; "The Wolver­ine Foun­da­tion", 2006; Abramov and Wozen­craft, 2008; Nowak, 1999; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• 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

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  17.3 years

  Max Planck Institute for Demographic Research

Be­hav­ior

In gen­eral, wolver­ines are soli­tary, only com­ing to­gether to mate. They are ter­ri­to­r­ial and do not tol­er­ate in­di­vid­u­als of the same sex. Ter­ri­to­ries are marked with se­cre­tions from anal scent glands and urine. Wolver­ines also spray their food caches with scent gland se­cre­tions to dis­cour­age other an­i­mals from raid­ing them. They are noc­tur­nal but can be ac­tive dur­ing the day. In areas where there are ex­tended times of light or dark­ness, wolver­ines may al­ter­nate three- to four-hour pe­ri­ods of ac­tiv­ity and sleep. Wolver­ines do not ap­pear to be both­ered by snow and are ac­tive year-round, even in the most se­vere weather. Wolver­ines are known for their fe­roc­ity and have been known to at­tack black bears and wolves over food. Wolver­ines are mainly ter­res­trial and move with a lop­ing gal­lop. They can climb trees with great speed and are ex­cel­lent swim­mers. Wolver­ines gal­lop with great en­durance, some­times mov­ing 10 to 15 km with­out rest, al­though their speed prob­a­bly does not ex­ceed 15 km per hour. They may cover up to 45 km in one day in their ac­tiv­i­ties. Play has been ob­served be­tween mates and be­tween sib­lings as well as be­tween kits and their moth­ers. Wolver­ines are also known to play with ob­jects. ("Alaska Fish and Wildlife Ser­vice", 2007; "AnAge: The An­i­mal Aging and Longevity Data­base", 2005; "The Wolver­ine Foun­da­tion", 2006; "United States Fish and Wildlife Ser­vice", 2008; "Wolver­ine", 2009; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Key Behaviors
• terricolous
• diurnal
• nocturnal
• motile
• sedentary
• solitary

• Range territory size

  600 to 2000 km^2

Home Range

Wolver­ines have large home ranges and may de­fend smaller ter­ri­to­ries. Males have home ranges of 600 to 1000 square kilo­me­ters. Fe­male home ranges are 50 to 350 square kilo­me­ters. Al­though, home range size varies sea­son­ally and home ranges can cover as much as 2,000 sq km in win­ter. Males and fe­males de­fend their range and mark it with scent from their anal glands. Pop­u­la­tion den­si­ties of wolver­ines are low be­cause of their re­quire­ments for very large home ranges. ("United States Fish and Wildlife Ser­vice", 2008; "Wolver­ine", 2009; Abramov and Wozen­craft, 2008; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

Com­mu­ni­ca­tion and Per­cep­tion

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. ("En­cy­clo­pe­dia Bri­tan­nica", 2009; "The Wolver­ine Foun­da­tion", 2006; Lofroth, et al., 2007; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Communication Channels
• acoustic
• chemical

• Other Communication Modes
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

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. ("The Wolver­ine Foun­da­tion", 2006; "Wolver­ine", 2009; "Alaska Fish and Wildlife Ser­vice", 2007; "En­cy­clo­pe­dia Bri­tan­nica", 2009; "The Wolver­ine Foun­da­tion", 2006; "United States Fish and Wildlife Ser­vice", 2008; "Wolver­ine", 2009; Burt, 1948; Lofroth, et al., 2007; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • scavenger
• omnivore

• Animal Foods
• birds
• mammals
• eggs
• carrion

• Foraging Behavior
• stores or caches food

Pre­da­tion

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "United States Fish and Wildlife Ser­vice", 2008; Lofroth, et al., 2007; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

• Known Predators

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

Ecosys­tem Roles

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). ("Alaska Fish and Wildlife Ser­vice", 2007; "The Wolver­ine Foun­da­tion", 2006; Burt, 1948; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

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. ("Alaska Fish and Wildlife Ser­vice", 2007; "United States Fish and Wildlife Ser­vice", 2008; Burt, 1948)

• Positive Impacts
• body parts are source of valuable material

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

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. ("The Wolver­ine Foun­da­tion", 2006; Abramov and Wozen­craft, 2008; Pa­sitsch­niak-Arts and Lar­iv­iere, 1995; Roel, et al., 2006)

• Negative Impacts
• injures humans
• crop pest

Con­ser­va­tion Sta­tus

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 Least Con­cern, though the Eu­ro­pean pop­u­la­tions are at higher risk. 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. ("United States Fish and Wildlife Ser­vice", 2008; Abramov and Wozen­craft, 2008; Roel, et al., 2006)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

De­spite the fact that wolver­ines have been claimed as an em­blem­atic an­i­mal by the state of Michi­gan ("The Wolver­ine State"), ev­i­dence sug­gests that wolver­ines did not his­tor­i­cally occur there. The "Wolver­ine State" ap­pela­tion most likely came from the fact that De­troit was a major fur trad­ing post for wolver­ine trap­pers. Wolver­ines are also known as glut­ton, skunk bear, In­dian devil, and car­ca­jou. ("Alaska Fish and Wildlife Ser­vice", 2007; Burt, 1948)

Con­trib­u­tors

Liz Bal­lenger (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Matthew Sygo (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Vin­cent Patsy (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Phil Myers (ed­i­tor, in­struc­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor, Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Ref­er­ences

2007. "Alaska Fish and Wildlife Ser­vice" (On-line). Ac­cessed April 10, 2009 at http://​www.​adfg.​state.​ak.​us/​pubs/​notebook/​furbear/​wolverin.​php.

2005. "AnAge: The An­i­mal Aging and Longevity Data­base" (On-line). Ac­cessed April 09, 2009 at http://​genomics.​senescence.​info/​species/​entry.​php?​species=Gulo_​gulo.

2009. "En­cy­clo­pe­dia Bri­tan­nica" (On-line). Ac­cessed April 10, 2009 at http://​www.​britannica.​com/​EBchecked/​topic/​646740/​wolverine.

2006. "The Wolver­ine Foun­da­tion" (On-line). Ac­cessed April 11, 2009 at http://​www.​wolverinefoundation.​org/​specacct.​htm.

2008. "United States Fish and Wildlife Ser­vice" (On-line). Ac­cessed April 10, 2009 at http://​ecos.​fws.​gov/​speciesProfile/​SpeciesReport.​do?​spcode=A0FA.

2009. "Wolver­ine" (On-line). Ac­cessed April 11, 2009 at http://​www.​wolverines-wolverines.​com/​.

Abramov, B., C. Wozen­craft. 2008. "In­ter­na­tional Union for the Con­ser­va­tion of Na­ture 2008 Red List" (On-line). Ac­cessed April 08, 2009 at http://​www.​iucnredlist.​org/​details/​9561.

Burt, W. 1948. The mam­mals of Michi­gan. Ann Arbor, MI: Uni­ver­sity of Michi­gan Press.

Copeland, J. 1996. Bi­ol­ogy of the wolver­ine in cen­tral Idaho. MSc The­sis.

Lofroth, E., J. Krebs, W. Har­rower, D. Lewis. 2007. Food habits of wolver­ine Gulo gulo in mon­tane ecosys­tems of British Co­lum­bia, Canada. Wildlife Bi­ol­ogy, 13: 13-37.

Nowak, R. 1999. Walker's mam­mals of the World. Bal­ti­more: Johns Hop­kins Uni­ver­sity Press.

Pa­sitsch­niak-Arts, M., S. Lar­iv­iere. 1995. Gulo gulo. Mam­malian Species, 499: 1-10.

Roel, M., A. Landa, v. Jiska, J. Lin­nell, R. An­der­sen. 2006. Im­pact of in­fra­struc­ture on habi­tat se­lec­tion of wolver­ines (Gulo gulo). Wildlife Bi­ol­ogy Sep­tem­ber 2006 : Vol. 12, Issue 3, pg(s) 285-295, Vol. 12, Issue 3: 285-95.

Rug­giero, L., K. McK­elvey, K. Aubry, J. Copeland, D. Pletscher. 2007. Wolver­ine Con­ser­va­tion and Man­age­ment. Jour­nal of Wildlife Man­age­ment, 71(7): 2145-46. Ac­cessed April 10, 2009 at http://​www.​bioone.​org/​doi/​abs/​10.​2193/​2007-053.