Today humans have bred hundreds of different domestic dog breedsâ€”some of which could never survive in the wild. Despite their many shapes and sizes all domestic dogs, from Newfoundlands to pugs, are members of the same speciesâ€”Canis familiaris. Although they have domestic temperaments, these dogs are related to wolves, foxes, and jackals.
Domestic dogs serve as more than companions; many earn their keep by working hard. Dogs herd livestock, aid hunters, guard homes, and perform police and rescue work. Some special animals even guide the blindâ€”a poignant symbol of the dog's longstanding role as man's best friend.