Grey wolf (Canis lupus)

Also known as: Arctic Wolf, Common Wolf, Gray Wolf, Mexican Wolf, Plains Wolf, Timber Wolf, Tundra Wolf, Wolf
  
French: Loup, Loup Gris, Loup Vulgaire
Spanish: Lobo
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderCarnivora
FamilyCanidae
GenusCanis (1)
SizeMale total length: 1.65 m (2)
Female total length: 1.59 m (2)
Height: 66 – 81 cm (3)
Male weight: 20 – 70 kg (3)
Female weight: 16 – 50 kg (3)
Top facts

The grey wolf is classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES, except for populations from Bhutan, Nepal, India and Pakistan, which are listed on Appendix I (4).

The world’s largest wild canid, the iconic grey wolf (Canis lupus) has been a source of both fear and respect, inspiring a rich cultural history (2) (5). In general appearance, this species resembles a large domestic dog, but has longer legs, larger feet, a narrower chest and a straight tail (2) (3). The fur is thick, with an outer layer composed of coarse guard hairs, below which a soft undercoat is present. The coat undergoes an annual moult in late spring, with a short summer coat growing simultaneously, which continues to develop into a winter coat in the autumn and winter (3). The most common coat colour is grey flecked with black, with lighter underparts, but individuals and populations also occur that are red, brown, black or almost pure white (2). The grey wolf’s sensitive ears and nose help it to track down prey, while the long legs enable it to make high-speed, lengthy pursuits (2).

Historically, the grey wolf held the title of the world’s most widely distributed land mammal. It ranged throughout much of the northern hemisphere, from Mexico, north through North America to the Arctic, and throughout most of Eurasia, as far south as southern India. Today, however, this species has a more restricted distribution, occurring mainly in wilderness and remote areas of Canada, Alaska, northern USA, Europe and Asia, and is extinct in parts of Western Europe, Mexico and the USA (1). There are seven Eurasian and five North American subspecies of grey wolf currently recognised, although subspecies are subjectively based so can change (2).

In accordance with its expansive range and adaptable nature, the grey wolf can be found in a wide variety of northern habitats where suitable food occurs, including forests, tundra, taiga, deserts, plains and mountains (1) (5). It is generally absent from heavily populated human settlements and areas of intensive cultivation (3).

Highly social and intelligent, the grey wolf is an efficient predator, capable of working together with other individuals to bring down large prey, ten times the size of an individual wolf (5). This species is most commonly found in packs, particularly in winter, usually numbering around 5 to 12 related individuals, although pairs and lone wolves also frequently occur (2) (5). Within the pack there is a clear dominance hierarchy, with the breeding pair possessing a strong, year-round pair bond. The breeding pair dominates the rest of the pack, which are usually the offspring (2). Packs may range over territories spanning 75 to 2,500 square kilometres depending on prey density. In order to advertise territorial boundaries and avoid encounters with other packs, grey wolf packs employ scent-marking and howling (2) (5). On occasions when packs meet violent fights occur, often resulting in fatalities (5).

While grey wolves have a varied diet, prey mostly comprises large ungulates, such as moose, caribou, deer, elk and wild boar (1). Smaller animals, livestock, carrion, berries and refuse may also be taken (1) (5). Prey is hunted down and often pursued in a chase which can last between 100 metres and 5 kilometres (2). The grey wolf’s keen observational skills enable packs to identify and single out individuals that are young, old or in poor condition (2) (5). Attacks usually focus on the rump of larger prey and on the head, shoulders, flanks and rump of smaller animals. On average, the grey wolf consumes 2.5 to 6.3 kilograms of food per day, and will cache surplus food in the form of prey parts or regurgitated chunks (2).

The grey wolf breeds between January and April, with the exact timing depending on latitude (2). Unless food is particularly abundant, only the dominant pair will breed, with the reproduction of other mature females suppressed by aggression and direct interference with copulation attempts by the dominant individuals (3). The dominant female bears a litter of 1 to 11 offspring (typically 6) in the spring after a gestation period of 9 weeks (2). The cubs are raised in a den located in a hole, cave, pit or hollow log, and are weaned at 8 to 10 weeks old. Starting at about three weeks of age, prey parts and regurgitated scraps are provided (2). If food is plentiful, the cubs are ready to travel with the pack at five months old, and by the next breeding season most juveniles leave the pack and disperse (6). Reproductive maturity generally is reached at 22 to 46 months, and lifespan in the wild can reach up to 13 years (6).

The grey wolf has a long history of persecution, as well as hunting and trapping for its fur, which has reduced its historical range by almost a third (1) (5). The greatest levels of persecution occurred in developed areas of Europe, Asia, Mexico and the United States, leading to massive declines and extermination in many regions primarily via poisoning (1) (6). Fortunately, since around 1970, legal protection, land-use changes and shifts in human populations away from rural areas to cities have halted the grey wolf’s decline and allowed natural recolonisation of parts of Western Europe and the USA (1). By contrast, legal protection is lacking in many developing countries, and persecution remains widespread. Habitat loss and fragmentation are also having a significant and growing impact of grey wolf populations. Despite these threats, the grey wolf is not considered to be threatened, its range remains large, and its overall population is stable (1). This should not, however, obscure the precarious status of some subspecies and regional populations, which require conservation action to ensure their survival (2).

Due to the large disparity in the grey wolf’s status in different parts of its range, conservation action and protection is highly variable. This species is subjected to regulated harvesting in Alaska and Canada, and is protected in the USA, Mexico and many European countries, with captive breeding and reintroduction efforts underway in the southwest USA, where the Mexican Wolf Recovery Program is working to restore extirpated populations of the Mexican wolf (Canis lupus baileyi) (1) (2). The grey wolf is also protected in China, India and Pakistan, although enforcement is lacking (2). In other parts of the grey wolf’s range, such as most of the Middle East, central Asia, and Russia the grey wolf has no legal protection. This is not a cause for concern in areas where this species is abundant, and indeed, sustainable utilisation of its fur occurs in countries such as Canada and Russia, as well as control and reduction programs (1) (2). Nevertheless, improved enforcement of existing protection areas, and conservation efforts targeting declining populations of this charismatic species would be beneficial.

For more information on the grey wolf and its conservation, visit:

Authenticated (24/01/2011) by Dr L.D. Mech, Co-Chair of the IUCN/SSC Wolf Specialist Group
http://www.davemech.org

  1. IUCN Red List (September, 2009)
    http://www.iucnredlist.org/
  2. Mech, L.D. and Boitani, L. (2003) (Eds) Wolves, Behaviour, Ecology and Conservation. University of Chicago Press.
  3. Mech, L.D. and Boitani, L. (2004) Grey Wolf Canis lupus (Linnaeus, 1758) In: Sillero-Zubriri, C., Hoffmann, M. and MacDonald, D.W. (Eds) Canids: Foxes, Wolves, Jackals and Dogs – 2004 Status Survey and Conservation Action Plan. IUCN, Gland, Switzerland and Cambridge, UK.
  4. CITES (September, 2009)
    http://www.cites.org/
  5. Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
  6. Mech, L.D. (January, 2011) Pers. comm.