Wolf, wild, dog-like carnivorous mammal, once widespread in North America and Eurasia, especially the grey wolf (Canis lupus), which is now restricted to both continents. It is powerfully built with a wide head and neck, muscular limbs, large feet and a deep-chested body; the tail is long and bushy. It has earned a reputation for savagery and cunning from occasional attacks on livestock and human beings. They frequently live in collective "companies". Length: to 2m, including the tail. Family Canidae.