Wolves belong to the class Mammalia, the order Carnivora, the family Canidae and the genus Canis. There are at least two species of wolves, including the grey wolf (lupus) and the red wolf (rufus). Some consider lycaon to be its own species, whereas others consider it a subspecies of lupus.
Many consider the gray wolf to be the ancestor of the domestic dog. Gray wolves are by far the most numerous of the two species of wolves, living throughout Asia, Canada, Alaska, parts of Greenland and parts of the northern United States. The gray wolf is rare in Europe, and even in those places where it still lives the it has seen its numbers diminished by human hunting and urbanization. The red wolf has a much smaller geographical range than gray wolf, and makes its home in the southeastern United States. Despite its name, the fox-like maned wolf is not a true wolf.
Wolves live in groups called packs that possess a hierarchical structure. The dominant male leads the pack, and mates with the dominant female. Wolf packs travel long distances to find prey, and members of the pack work together in order to make a kill. Food items on a wolf's menu range from birds and small mammals to elk and moose. Upon making a big kill, wolves may each eat up to 20 pounds of food in one sitting.