The chief and type genus of the family Canidae that includes the domestic dog, the wolves, and jackals, and sometimes in older classifications, the foxes.

Timber wolf.

The gray wolf, commonly referred to as tundra wolf or timber wolf, is the largest of all wild canids, although its size varies noticeably throughout its large range including Minnesota, Michigan, and Montana in the United States and many remote areas of Canada, Alaska and Europe.

Current canine taxonomy indicates that there are three species of wolves in existence today, all members of the genus Canis.

The gray wolf (Canis lupes); (tundra wolf, timber wolf, arctic wolf, buffalo wolf, lobo wolf, etc.) is the largest species with representatives found in North America, Europe, Scandinavia, Middle East, India, and Asia.

The second species, Canis rufus, "red wolf" is a taxa under challenge as to whether it is truly a species of wolf or simply a hybrid offspring of gray wolves mating with coyotes.

The third species of wolf is the Ethiopian wolf (Canis simensis) which lives in Africa and Ethiopia and has previously been classified as a jackal until DNA research proved it to be a true wolf.

1. In astronomy, the Great Dog, a southern constellation between Puppis and Orion, containing Sirius, the Dog Star, the brightest of the stars.
2. A constellation southeast of Orion which also contains Sirius; also called, "Great Dog".

A constellation east of Orion which contains Procyon; also called, "Little Dog".