Animal Diversity Web

Ge­o­graphic Range

The orig­i­nal range of Canis lupus con­sisted of the ma­jor­ity of the North­ern hemi­sphere -- from the Arc­tic con­tin­u­ing south to a lat­i­tude of 20° S, which runs through south­ern Cen­tral Mex­ico, north­ern Africa, and south­ern Asia. How­ever, due to habi­tat de­struc­tion, en­vi­ron­men­tal change, per­se­cu­tion by hu­mans, and other bar­ri­ers to pop­u­la­tion growth, gray wolf pop­u­la­tions are now found only in a few areas of the con­tigu­ous United States, Alaska, Canada, Mex­ico (a small pop­u­la­tion), and Eura­sia.

• Biogeographic Regions
• nearctic
  • native
• palearctic
  • native

• Other Geographic Terms
• holarctic

Habi­tat

Gray wolves are one of the most wide rang­ing land an­i­mals. They oc­cupy a wide va­ri­ety of habi­tats, from arc­tic tun­dra to for­est, prairie, and arid land­scapes.

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• tundra
• taiga
• chaparral
• forest
• scrub forest
• mountains

Phys­i­cal De­scrip­tion

The largest of ap­prox­i­mately 41 wild species of canids, gray wolves vary in size based pri­mar­ily on ge­o­graphic lo­cal­ity, with south­ern pop­u­la­tions gen­er­ally smaller than north­ern pop­u­la­tions. Total body length, from tip of the nose to tip of the tail, is from 1000 to 1300 mm in males, and 870 to 1170 mm in fe­males. Tail length ranges be­tween 350 to 520 mm. Males can weigh from 30 to 80 kg, with an av­er­age of 55 kg, fe­males can weigh from 23 to 55 kg, with an av­er­age of 45 kg. Height (mea­sured from base of paws to shoul­der) gen­er­ally ranges from 60 to 90 cm. Dis­tance be­tween the ca­nines is around 4 cm.

Fur color of gray wolves also varies ge­o­graph­i­cally, rang­ing from pure white in Arc­tic pop­u­la­tions, to mix­tures of white with gray, brown, cinam­mon, and black to nearly uni­form black in some color phases.

North Amer­i­can pop­u­la­tions have three dis­tinct color phases. The nor­mal phase is char­ac­ter­ized by vary­ing mix­tures of white with shades of black, gray, cin­na­mon, and brown on the upper parts of the an­i­mal. The back is usu­ally more pro­foundly black, and the muz­zle, ears, and limbs have cinam­mon col­oration as well. Under parts are whitish and the tail is con­spic­u­ously black over the tail gland, and paler below to the tip, which is nearly pure black. The black phase of North Amer­i­can pop­u­la­tions is char­ac­ter­ized by the upper parts vary­ing from brown to black, with specks of white; the un­der­parts are paler in tone, and there is often a pure white me­dial pec­toral spot. The third color phase oc­curs dur­ing the first pelage of young wolves. The upper parts are drab-gray, over­laid with brown­ish-black. The un­der­parts are paler as well, and the ears vary from black to buffy, de­pend­ing on the sub­species (Young 1944).

Gray wolves have a dense un­der­fur layer, pro­vid­ing them with ex­cel­lent in­su­la­tion against cold con­di­tions.

Gray wolves can be dis­tin­guished from red wolves (Canis rufus) by their larger size, broader snout, and shorter ears. They are dis­tin­guished from coy­otes (Canis la­trans) by being 50 to 100% larger and hav­ing a broader snout and larger feet.

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  23.0 to 80 kg

  50.66 to 176.21 lb

• Range length

  870 to 1300 mm

  34.25 to 51.18 in

Re­pro­duc­tion

The dom­i­nant pair in a grey wolf pack are the only mem­bers that breed. This pair is monog­a­mous al­though, with the death of an alpha in­di­vid­ual, a new alpha male or fe­male will emerge and take over as the mate.

• Mating System
• monogamous
• cooperative breeder

Breed­ing oc­curs be­tween the months of Jan­u­ary and April, with north­ern pop­u­la­tions breed­ing later in the sea­son than south­ern pop­u­la­tions. Fe­male gray wolves choose their mates and often form a life-long pair bond. Gray wolf pairs spend a great deal of time to­gether. Fe­male gray wolves come into es­trus once each year and lasts 5 to 14 days, mat­ing oc­curs dur­ing this time. After mat­ing oc­curs, the fe­male digs a den in which to raise her young. The den is often dug with an en­trance that slopes down and then up again to a higher area to avoid flood­ing. Pups are born in the den and will re­main there for sev­eral weeks after birth. Other dens are under cliffs, under fallen trees, and in caves. The ges­ta­tion pe­riod lasts be­tween 60 and 63 days, lit­ter size ranges from one to four­teen, with the av­er­age size being six or seven pups. Pups re­main in the den until they are 8 to 10 weeks old. Fe­males stay with their pups al­most ex­clu­sively for the first 3 weeks. Pups are cared for by all mem­bers of the pack. Until they are 45 days old the pups are fed re­gur­gi­tated food by all pack mem­bers. They are fed meat pro­vided by pack mem­bers after that age. Fe­male pups reach ma­tu­rity at two years of age, while males will not reach full ma­tu­rity until three years of age. Most young gray wolves dis­perse from their natal pack when they are be­tween 1 and 3 years old.

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• viviparous

• Breeding interval

  Gray wolves breed once each year.

• Breeding season

  Gray wolves breed between January and March, depending on where they are living.

• Range number of offspring

  5.0 to 14.0

• Average number of offspring

  7.0

• Average number of offspring

  6

  AnAge

• Range gestation period

  63.0 (high) days

• Average weaning age

  45.0 days

• Range age at sexual or reproductive maturity (female)

  2.0 to 3.0 years

• Range age at sexual or reproductive maturity (male)

  2.0 to 3.0 years

Gray wolf pups are born blind and deaf. They weigh ap­prox­i­mately 0.5 kg and de­pend on the mother for warmth. At ten to fif­teen days of age, the pups' blue eyes open, but they only have con­trol over their front legs, thus crawl­ing is their only mode of mo­bil­ity. Five to ten days later, the young are able to stand, walk, and vo­cal­ize. Pups are cared for by all mem­bers of the pack. Until they are 45 days old the pups are fed re­gur­gi­tated food by all pack mem­bers. They are fed meat pro­vided by pack mem­bers after that age. Dur­ing the 20th to 77th day, the pups leave the den for the first time and learn to play fight. In­ter­ac­tions at this time, as well as the dom­i­nance sta­tus of the mother, ul­ti­mately de­ter­mines their po­si­tion in the pack hi­er­ar­chy. Wolf pups de­velop rapidly, they must be large and ac­com­plished enough to hunt with the pack with the onset of win­ter. At ap­prox­i­mately ten months old, the young begin to hunt with the pack.

• Parental Investment
• no parental involvement
• altricial
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• post-independence association with parents
• extended period of juvenile learning
• maternal position in the dominance hierarchy affects status of young

Lifes­pan/Longevity

Gray wolves may live thir­teen years in the wild, though av­er­age lifes­pan is 5 to 6 years. As adults they usu­ally die from old age or from in­juries re­ceived while hunt­ing or fight­ing with other wolves. In cap­tiv­ity they may live to be fif­teen years of age.

• Range lifespan
  Status: wild

  13.0 (high) years

• Average lifespan
  Status: wild

  5.0 years

• Range lifespan
  Status: captivity

  15.0 (high) years

• Average lifespan
  Status: wild

  10.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  20.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Sex: female
  Status: wild

  13.7 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Sex: female
  Status: captivity

  16.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: wild

  16.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  20.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Gray wolves are highly so­cial, pack-liv­ing an­i­mals. Each pack com­prises two to thirty-six in­di­vid­u­als, de­pend­ing upon habi­tat and abun­dance of prey. Most packs are made up of 5 to 9 in­di­vid­u­als. Packs are typ­i­cally com­posed of an alpha pair and their off­spring, in­clud­ing young of pre­vi­ous years. Un­re­lated im­mi­grants may also be­come mem­bers of packs.

There is a strong dom­i­nance hi­er­ar­chy within each pack. The pack leader, usu­ally the alpha male, is dom­i­nant over all other in­di­vid­u­als. The next dom­i­nant in­di­vid­ual is the alpha fe­male, who is sub­or­di­nate only to the alpha male. In the event that the alpha male be­comes in­jured or is oth­er­wise un­able to main­tain his dom­i­nance, the beta male will take his place in the hi­er­ar­chy. Alpha males typ­i­cally leave the pack if this oc­curs, but this is not al­ways the case. Rank within the pack hi­er­ar­chy de­ter­mines which an­i­mals mate and which eat first. Rank is demon­strated by pos­tural cues and fa­cial ex­pres­sions, such as crouch­ing, chin touch­ing, and rolling over to show the stom­ach.

Each year, gray wolf packs have a sta­tion­ary and no­madic phase. Sta­tion­ary phases occur dur­ing the spring and sum­mer, while pups are being reared. No­madic phases occur dur­ing the fall and win­ter. Wolf move­ments are usu­ally at night and cover long dis­tances. Daily dis­tance trav­eled can be up to 200 km, the usual pace is 8 km/hr. Wolves can run at speeds up to 55 to 70 km/hr.

• Key Behaviors
• cursorial
• terricolous
• diurnal
• nocturnal
• motile
• nomadic
• territorial
• social
• dominance hierarchies

Home Range

The ter­ri­tory of a pack ranges from 130 to 13,000 square kilo­me­ters, and is de­fended against in­trud­ers.

Com­mu­ni­ca­tion and Per­cep­tion

Rank is com­mu­ni­cated among wolves by body lan­guage and fa­cial ex­pres­sions, such as crouch­ing, chin touch­ing, and rolling over to show their stom­ach.

Vo­cal­iza­tions, such as howl­ing al­lows pack mem­bers to com­mu­ni­cate with each other about where they are, when they should as­sem­ble for group hunts, and to com­mu­ni­cate with other packs about where the bound­aries of their ter­ri­to­ries are. Scent mark­ing is or­di­nar­ily only done by the alpha male, and is used for com­mu­ni­ca­tion with other packs.

• Perception Channels
• tactile
• chemical

Food Habits

Gray wolves are car­ni­vores. They hunt prey on their own, in packs, steal the prey of other preda­tors, or scav­enge car­rion. Prey is lo­cated by chance or scent. An­i­mals in­cluded in the diet of gray wolves varies ge­o­graph­i­cally and de­pends on prey avail­abil­ity. Wolves pri­mar­ily hunt in packs for large prey such as moose, elk, bison, musk oxen, and rein­deer. Once these large un­gu­lates are taken down, the wolves at­tack their rump, flank, and shoul­der areas. Wolves con­trol prey pop­u­la­tions by hunt­ing the weak, old, and im­ma­ture. A wolf can con­sume up to 9 kg of meat at one meal. Wolves usu­ally uti­lize the en­tire car­cass, in­clud­ing some hair and bones. Smaller prey such as beavers, rab­bits, and other small mam­mals are usu­ally hunted by lone wolves, and they are a sub­stan­tial part of their diet. Wolves may also eat live­stock and garbage when it is avail­able.

• Primary Diet
• carnivore
  • eats terrestrial vertebrates

• Animal Foods
• mammals
• carrion

Pre­da­tion

Few an­i­mals prey on gray wolves. Wolves and coy­otes are highly ter­ri­to­r­ial an­i­mals so wolves from other packs and coy­otes will at­tack wolves that are alone or young. They will kill pups if they find them.

• Known Predators

  • coyotes (Canis latrans)
  • gray wolves (Canis lupus)

Ecosys­tem Roles

As top preda­tors, gray wolves are im­por­tant in reg­u­lat­ing pop­u­la­tions of their prey an­i­mals.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

His­tor­i­cally, the fur of grey wolves was used for warmth. As top preda­tors in many ecosys­tems, wolves are im­por­tant in con­trol­ling pop­u­la­tions of their prey.

Wolves are im­por­tant in our cul­ture, many peo­ple be­lieve they sym­bol­ize the spirit of wilder­ness. Wolf prod­ucts, in­clud­ing posters, books, and t-shirts are very pop­u­lar. Wolf eco­tourism is a major source of rev­enue for parks and re­serves.

• Positive Impacts
• body parts are source of valuable material
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Gray wolves may some­times kill live­stock. The ex­tent of live­stock loss to wolves is often over­stated, wolves typ­i­cally pre­fer their wild prey.

Con­ser­va­tion Sta­tus

"Few an­i­mals have ever haunted our dreams or fired our imag­i­na­tions more than the wolf. Un­for­tu­nately, by the early part of this cen­tury, man had al­most ex­ter­mi­nated the wolf from the lower 48 states. The re­cov­ery of the wolf is be­com­ing an im­pres­sive con­ser­va­tion suc­cess story and a gift to fu­ture gen­er­a­tions" (Bruce Bab­bitt, Sec­re­tary of the In­te­rior).

Wolves play an im­por­tant role in the ecosys­tem by con­trol­ling nat­ural prey pop­u­la­tions and re­mov­ing weak in­di­vid­u­als. As set­tle­ment in­creased, the be­lief that live­stock was en­dan­gered by wolf pop­u­la­tions also in­creased. As such, the fre­quency of hunt­ing the gray wolf ex­ploded. The pop­u­la­tions were nearly erad­i­cated. Cur­rently in the lower 48 United States, about 2,600 gray wolves exist, with nearly 2,000 in Min­nesota (com­pared to the few hun­dred liv­ing there in the mid-20th cen­tury). Suc­cess­ful re­cov­ery plans have been de­vel­oped through­out the coun­try. These plans eval­u­ate the pop­u­la­tions to de­ter­mine dis­tri­b­u­tion, abun­dance, and sta­tus. The main cause of pop­u­la­tion de­clines has been habi­tat de­struc­tion and per­se­cu­tion by hu­mans. But the rein­tro­duc­tion of gray wolves into pro­tected lands has greatly in­creased the like­li­hood of their sur­vival in North Amer­ica. Pop­u­la­tions in Alaska and Canada have re­mained steady and are fairly nu­mer­ous. Cur­rently the State of Alaska man­ages 6,000 to 8,000 gray wolves and Canada's pop­u­la­tions are es­ti­mated at about 50,000. The wolves in Canada are man­aged by provin­cial gov­ern­ments and are not cur­rently threat­ened.

In west­ern Eura­sia gray wolf pop­u­la­tions have been re­duced to iso­lated rem­nants in Poland, Scan­di­navia, Rus­sia, Por­tu­gal, Spain, and Italy. Wolves were ex­ter­mi­nated from the British Isles in the 1700's and nearly dis­ap­peared from Japan and Green­land in the 20th cen­tury. Green­land's wolf pop­u­la­tions seem to have made a full re­cov­ery. The sta­tus of wolf pop­u­la­tions through­out much of east­ern Eura­sia is poorly known, but in many areas pop­u­la­tions are prob­a­bly sta­ble.

Gray wolves are listed were until re­cently listed as en­dan­gered by the U.S. Fish and Wildlife Ser­vice and as threat­ened by the state of Michi­gan DNR. Most U.S. pop­u­la­tions of gray wolves have now been delisted, ex­cept for ex­per­i­men­tal pop­u­la­tions of Mex­i­can gray wolves in the south­west. They are in CITES Ap­pen­dix II, ex­cept for pop­u­la­tions in Bhutan, India, Nepal and Pak­istan, which are in Ap­pen­dix I.

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  Endangered

• CITES

  Appendix I Appendix II

• State of Michigan List

  Threatened

Other Com­ments

Ex­cept for red wolves (Canis rufus), all liv­ing North Amer­i­can wolves are con­sid­ered to be Canis lupus -- a total (as of 1997) of 32 rec­og­nized sub­species.

Gray wolves are widely rec­og­nized to be the an­ces­tor of all do­mes­tic dog breeds (Canis lupus fa­mil­iaris), in­clud­ing feral forms such as din­gos (Canis lupus dingo) and New Guinea singing dogs (Canis lupus hal­stromi). Ge­netic ev­i­dence sug­gests that gray wolves were do­mes­ti­cated at least twice, and per­haps as many as 5 times, by hu­mans. Ar­ti­fi­cial se­lec­tion by hu­mans for par­tic­u­lar traits, in­clud­ing size, ap­pear­ance, ag­gres­sive­ness, loy­alty, and many de­sir­able, spe­cial­ized skills, has re­sulted in an as­ton­ish­ing array of do­mes­tic dog mor­pholo­gies. Do­mes­tic dogs vary in size from diminu­tive, 1.5 kg chi­huahuas to 90 kg giant mas­tiffs.

Con­trib­u­tors

Tanya Dewey (au­thor, ed­i­tor), An­i­mal Di­ver­sity Web.

Julia Smith (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

"A Short Course on Gray Wolves" (On-line). Ac­cessed De­cem­ber 9, 1999 at http://​www.​boomerwolf.​com/​graycors.​htm.

July 1998. "Gray Wolf (Canis lupus)" (On-line). Ac­cessed De­cem­ber 9, 1999 at http://​www.​fws.​gov/​r3pao/​wolf/​wolfindx.​html.

Jan­u­ary 16, 1997. "Gray Wolf" (On-line). Ac­cessed De­cem­ber 9, 1999 at http://​www.​kats-korner.​com/​graywolf.​html.

Dog Breed Info Cen­ter, 2000. "Dog Breeds in Al­pha­bet­i­cal Order" (On-line). Ac­cessed Feb­ru­ary 16, 2002 at http://​www.​dogbreedinfo.​com/​abc.​htm.

Kinder, A. 1995. "An­i­mal Di­ver­sity Web, Canis lupus dingo (Dingo)" (On-line). Ac­cessed Feb­ru­ary 19, 2002 at http://​animaldiversity.​ummz.​umich.​edu/​accounts/​canis/​c._​lupus_​dingo$narrative.​html.

McIn­tyre, R. 1993. A So­ci­ety of Wolves: Na­tional Parks and the Bat­tle Over the Wolf. Still­wa­ter, MN: Voyageur Press.

Mech, L. 1999. Gray Wolf. Pp. 141-143 in D Wil­son, S Ruff, eds. The Smith­son­ian Book of North Amer­i­can Mam­mals. Wash­ing­ton and Lon­don: Smith­son­ian In­sti­tu­tion Press.

Shetal, B. 1995. "An­i­mal Di­ver­sity Web, Canis lupus fa­mil­iaris (Dog)" (On-line). Ac­cessed Feb­ru­ary 19, 2002 at http://​animaldiversity.​ummz.​umich.​edu/​accounts/​canis/​c._​lupus_​familiaris$narrative.​html.

Strauber, J. June 12, 1997. "The Gray Wolf" (On-line). Ac­cessed De­cem­ber 9, 1999 at http://​www.​hillsborough.​k12.​nj.​us/​hhs/​endspeci/​canislupus.​html.

Young, S., E. Gold­man. 1944. The Wolves of North Amer­ica. Wash­ing­ton D.C.: The Amer­i­can Wildlife In­sti­tute.

Zgurski, J. 2002. "The Be­hav­ior and Ecol­ogy of Wolves" (On-line). Ac­cessed Feb­ru­ary 16, 2002 at http://​www.​ualberta.​ca/​~jzgurski/.

Zgurski, J. 2002. "The Ori­gin of the Do­mes­tic Dog" (On-line). Ac­cessed Feb­ru­ary 16, 2002 at http://​www.​ualberta.​ca/​~jzgurski/dog.​htm.

Zgurski, J. 2002. "Wolf Tax­on­omy" (On-line). Ac­cessed Feb­ru­ary 16, 2002 at http://​www.​ualberta.​ca/​~jzgurski/taxa.​html.