A large male wolf may measure longer than 2 m (6.6 ft.) in total, of which about 25% is tail. It may stand almost 1 m (3 ft.) high at the shoulders. Weights range from 26 to 80 kg (57 to 176 lb.). The largest wolves are found in northwestern Canada. The colouration of wolves varies greatly—from snow white to coal black, with all the intermediate shades of cream, grey and brown.
These animals have a well-developed social hierarchy. The pack leader is usually the largest and strongest male and is followed in rank by younger or senile males, then the leader's mate, the other females, and finally the pups in order of strength. All members of the pack accept responsibility for the young: if both parents are hunting, other adults will care for their pups.
The wolf is the world's most widely distributed carnivore. Its natural range included all continents north of latitude 20 degrees north: Europe, Asia, North America and northern Africa. It occupies all habitats except tropical forests and deserts.
There have been very few cases of authenticated wolf attacks on humans in North America, and no known deaths.