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gray wolf

Canis lupus

What do they look like?

Gray wolves are the largest wild dog species in the world. They vary in size depending on where they are found, with southern populations being generally smaller than northern populations. Total body length, from tip of the nose to tip of the tail, is from 870 to 1,300 mm. Height (measured from base of paws to shoulder) generally ranges from 60 to 90 cm. Males are, on average, larger than females.

Fur color of gray wolves also varies depending on where they are living. Their color ranges from pure white in Arctic populations, to mixtures of white with gray, brown, cinammon, and black to nearly uniform black in some color phases. Their upperparts are generally darker and they have lighter fur on their undersides, the tail is tipped with black.


  • 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

Where do they live?

Gray wolves once ranged throughout the Northern hemisphere, from the Arctic south to southern 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.

What kind of habitat do they need?


How do they reproduce?


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. 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 five to fourteen, with the average size being seven pups. Female pups reach maturity at two years of age, while males will not reach full maturity until three years of age.

  • How often does reproduction occur?
    Gray wolves breed once each year.
  • Breeding season
  • Range number of offspring
    5.0 to 14.0
  • Average number of offspring
  • Average number of offspring
  • 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


  • 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

How long do they live?


How do they behave?

Gray wolves are very social, pack-living animals. Each pack is made up of two to thirty-six individuals, depending upon their habitat and the abundance of their prey. Most packs are made up of 5 to 9 individuals. Packs are typically made up of an alpha pair and their offspring, including their young from previous years.

There is a strong structure of dominance relationships within each pack. Each pack member has a position in those dominance relationships, called their 'rank'. The pack leader, usually the alpha male, is dominant over all other individuals. The next dominant individual is the alpha female. If the alpha male becomes injured, the next highest ranking male will take his place as alpha male. Rank within the pack determines which animals mate and which eat first.

Each year, gray wolf packs have stationary and nomadic phases. In the spring and summer, while pups are being reared, wolf packs remain in the same area. During the fall and winter wolf packs move around in search of food. Wolf movements are usually at night and may 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.

Home Range


How do they communicate with each other?



What do they eat?

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 by scent. What wolves eat depends on where they live and what kinds of prey are available. Wolves hunt in packs for large prey such as moose, elk, bison, musk oxen, and reindeer. Wolves help to keep prey populations healthy by hunting the weak, old, and sick animals. A wolf can consume up to 9 kg of meat at one meal. Wolves usually eat almost the entire carcass, including some hair and bones. Smaller animals, such as beavers, rabbits, and other small mammals are usually hunted by lone wolves. Wolves may also eat livestock and garbage when it is available.

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates

What eats them and how do they avoid being eaten?


What roles do they have in the ecosystem?


Do they cause problems?


How do they interact with us?



  • Ways that people benefit from these animals:
  • body parts are source of valuable material
  • ecotourism

Are they endangered?


Wolves play an important role in the ecosystem by controlling natural prey populations and removing weak individuals. Unfortunately, people who keep livestock believed that gray wolves posed a terrible threat to their herds and wolf extermination programs became widespread. Populations of gray wolves 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 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.


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.

Some more information...

Except for red wolves, all living North American wolves are considered to be gray wolves. There are 32 different kinds of gray wolves recognized in North America.

Gray wolves are the ancestor of all domestic dog breeds, including wild living dogs such as dingos and New Guinea singing dogs. In domesticating wolves, humans have selected them for particular traits, including size, appearance, aggressiveness, loyalty, and many special skills. The result is an astonishing array of domestic dog breeds that vary in size from diminutive, 1.5 kg chihuahuas to 90 kg giant mastiffs.


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



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University of Michigan Museum of ZoologyNational Science Foundation

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Smith, J. 2002. "Canis lupus" (On-line), Animal Diversity Web. Accessed October 06, 2015 at


University of Michigan