This species was one of the most widely distributed mammals in the northern hemisphere, but hunting pressures and increasing urbanization have greatly reduced its range.
All domestic dogs are descended from grey wolf, which began living alongside humans many thousands of years ago. The wolves were once common in the ancient forests of the Northern Hemisphere. Human hunters have wiped them out in most parts of the world.
Wolves maintain territorial boundaries, scent-marking regularly. The size and availability of prey seems to determine pack size. There can be up to 20 or more wolves in herds in Alaska, where they face strong and dangerous prey such as moose. Grey wolves are the largest dogs in the wild, and they live in packs of about ten individuals. A wolf pack has a strict hierarchy. The alpha dogs bond for life. The rest of the pack is largely made up of the alpha pair’s close relatives and their offspring. Pairs remain together for life.
In desert areas though, where food is more scarce, they may live as pairs, being lighter and quicker to catch smaller and faster quarry. In summer, pack members hunt alone for small animals such as hares. In winter the pack hunts together for much larger animals, such as deer or wild cattle. Grey wolves are strong runners and can travel 200 km (125 miles) in one night.
Grey wolves howl to communicate with pack members over long distances. Each individual can be identified by its howl.
They detect prey by smell and chase them down. The pack harries a victim until it becomes exhausted. The wolves then take turns to take a bite at its face and flanks until the victim collapses.
The female gives birth to 3 to 8 pups after a gestation of about 63 days. Born blind and hairless, the pups venture outside the den at 3 weeks, and the whole pack then helps to care for and play with them.
Distribution: Now confined to more remote areas in Canada, Michigan and Wisconsin in the USA, and Russia, as well as a few areas of Europe.
Habitat: Tundra, steppe, open woodland and forest.
Weight: 15 - 80 kg (33 - 176 lb); males and northern races are heavier.
Length: 130 - 200 cm (51 - 79 in); up to 87 cm (34 in) tall.
Maturity: 2 - 3 years.
Gestation Period: 60 - 63 days.
Breeding: 1 - 19, average 5 - 6; weaned by 70 days.
Food: Primarily carnivorous, mainly hunts ungulates such as bison, deer, sheep, goat and caribou.
Lifespan: 6 - 9 years; may live over 12 years in captivity.
Male grey wolves have broader muzzles and broader foreheads than females.
In spite of its name, the grey wolf’s coat colour is actually very variable.
The grey wolf’s coat is double-layered, with a weather resistant outer layer and an insulating undercoat.
There is slight webbing between the toes, to help the wolves walk over snowy ground without sinking into it.
Domestic dogs are directly descended from wolves.
There is a rigorous hierarchy in wolf packs. Usually only the dominant pair will breed, with other pack members helping to raise the cubs.