Gray Wolf Gray Wolf
Gray Wolf

Scientific Classification

Common Name
gray wolf, arctic wolf, tundra wolf, Mackenzie Valley wolf, timber wolf, plains wolf, Mexican wolf, lobo, European wolf, Eurasian wolf, common wolf, Iberian wolf, Turukhan wolf, Arabian wolf, steppe wolf, Asian desert wolf, Tibetan wolf
Genus Species
Canis lupus

Fast Facts

Like most canids, wolves have a high body, long legs, broad skull tapering to a narrow muzzle. The tail is bushy and coat has a thick, dense underfur. Colors vary from light to dark gray with black and white interspersed, to some individuals being solid black and solid white. Not to be confused with two additional, distinct wolf species: the red wolf, Canis rufus, and the Ethiopian wolf, Canis simensis.
Largest of the wild canid species. There is variation in average sizes according to region in which they are found. Wolves of Mexico, Italy and Arabia are smaller than those of North America. Average head/body length 1,000 to 1,600 mm (39.4 to 63 in.); tail length 350 to 560 mm (13.8 to 22 in.).
Males are usually larger than females
Male:  Range between 20 to 80 kg (44 to 176 lbs.); average 40 kg (88 lbs.)
Female:  Range between 18 to 55 kg (39.7 to 121 lbs.); average 37 kg (81.6 lbs.)
Carnivorous; primarily prey on large mammals such as deer, wapiti, moose, caribou, bison, muskox, and mountain sheep. Smallest prey taken consistently is beaver. An adult can consume as much as 9 kg (20 lbs.) in one feeding.
62 to 63 days
Estral Period
5 to 15 days
Nursing Duration
Average 45 days
Sexual Maturity
Approximately 22 months. Social structure may prevent breeding until older. The youngest captive pair to breed were 10 months.
Female:  Wild females have been recorded giving birth at 10 years old.
Life Span
Potential longevity 16 years
With the exception of humans, the gray wolf has the largest natural range of any living terrestrial mammal. Found in the U.S. except southeastern quarter, highlands of Mexico, Canada, Greenland, Libya, Egypt, and Eurasia with the exception of the southeastern corner.
Found in all habitats except tropical forests and arid deserts.
Global:  Approximately 150,000
Regional: Varies by location
IUCN: Mexico - Extinct in the wild; Italy – Vulnerable; Spain/Portugal – Conservation Dependant
CITES: Most populations Appendix II; in Pakistan, India, Nepal, and Bhutan Appendix I
USFWS:  Endangered and Threatened depending on location

Fun Facts

  1. Wolves use dens for the rearing of their young. Dens are sometimes constructed out of the vacated burrows of other animals, in rock crevices, or hollows in and around trees. It is common for wolves to reuse the same den. These structures are sometimes quite large with tunnels extending 2 to 4 m (6.5 to 13 ft.) underground to a chamber. Some dens have more than one entrance.
  2. Activity is diurnal. Wolves often travel long distances, covering ranges of up to 200 km (124 miles) per day. They travel at speeds of about 8 kph (4.9 mph) but can reach running speeds of up to 55 to 70 kph (34 to 43.5 mph). Additionally, gray wolves have been known to pursue prey for as long as 20 minutes covering distances of up to 5 km (3 miles).
  3. Wolves hunt in packs. They hunt by stealth, harrassment, and active chase, ultimately attacking the rump, flanks, and shoulders of large prey. Most attempts end in failure.
  4. Packs are usually composed of a mated pair that are the most dominant animals in the group, and their offspring of one or more years. The pack is led by an alpha male. The social hierarchy is established and maintained through aggressiveness, elaborate greetings, and submission.
  5. Gray wolves communicate using vocalizations, scent marking, and body language. Howling is used to communicate territorial cues over long distances and helps to bring the pack back together when they are dispersed. Each wolf has a distinct howl.
  6. In spite of their reputation as being a threat to humans, there are actually very few documented wolf/human attacks, and many of those that have been reported have not resulted in serious injury.

Ecology and Conservation

Wolves are predators and as such help control the populations of prey species; however they have been blamed for also taking livestock species. Studies have shown that these incidences are rare. Wolves have been hunted and trapped for sport, for their fur and for extermination. Many wolf populations have been eliminated from their historic ranges. Modern wolves are also at risk from canine parvovirus, parasitic heartworms and hybridization of the gene pool with coyotes and domestic dogs. Efforts to reintroduce wolfs into some of their historic ranges in the U.S. are meeting with success. There are populations now established in Montana, Wyoming, and Idaho with natural movement occurring into other states.


Nowak, R. M. Walker's Mammals of the World. Sixth edition. Baltimore: Johns Hopkins University Press, 1999.