In ecology, the term pariah dog refers to free-ranging dogs that occupy an ecological niche based on waste from human settlements. When used in this manner, the term describes a large percentage of dogs worldwide, especially in developing countries, Eastern Europe and the Balkans.
While most pariah dogs are free-ranging, not all free-ranging dogs are genetically pariah dogs. Though they are "outcasts" in the social sense, and thus may still be called pariahs by observers who are not cynologists, feral dogs may be of any or mixed breeds. Individual dogs may be stray pets, descended from strays, or from litters abandoned by owners. They may live in packs, pairs, or singly.
All authentic strains of pariah dogs are at risk of losing their genetic uniqueness by interbreeding with purebred and mixed-breed strays. To prevent this from happening, some strains of pariah dogs are becoming formally recognized, registered, and pedigreed as breeds in order to preserve the pure type.
The United Kennel Club (United States) recognizes purebred dogs bred for chasing large game in the Sighthound & Pariah Group. Included in this group are breeds that are either of early origin or modern reconstructions of early breeds or types. The group includes the Afghan Hound, Azawakh, Basenji, Borzoi, Canaan Dog, Carolina Dog, Chart Polski (Polish Greyhound), Cirneco dell'Etna, Greyhound, Hungarian Greyhound, Ibizan Hound, Irish Wolfhound, New Guinea Singing Dog, Pharaoh Hound, Portuguese Podengo, Rhodesian Ridgeback, Saluki, Scottish Deerhound, Sinhala Hound, Silken Windhound, Sloughi, Spanish Greyhound, Thai Ridgeback, Whippet, and Xoloitzcuintli.