Although black tongues are stereotypically associated with Chow Chows, the trait of partially or totally black tongues is a characteristic of many different breeds of dog. This is because the Chow Chow is one of the oldest known dog breeds, and many different dog families are descended from this breed, according to PawPosse.com.
Chow Chows are part of the Spitz family, which includes dogs of Arctic and East Asian origin. As a result of this large family, many dog breeds are genetically disposed to having totally or partially black tongues.
These breeds include: Airedale, Akita, Australian Cattle Dog, Australian Shepherd, Belgian Sheepdog, Belgian Tervuren, Belgian Malinois, Bichon Frise, Bouvier de Flandres, Bull Mastiff, Cairn Terrier, Chinese Shar-Pei, Collie, Cocker Spaniel, Dalmatian, Doberman Pinscher, English Setter, Eurasier, Fila Brasileiro, Flat-coated Retriever, German Shepherd, Golden Retriever, Gordon Setter, Great Pyrenees, Irish Setter, Kai Ken, Keeshond, Kerry Blue Terrier, Korean Jindo, Laborador Retriever, Mountain Cur, Newfoundland, Pomeranian, Pug, Rodesian Ridgeback, Rottweiler, Shiba Inu, Siberian Husky, Soft-Coated Wheaten Terrier and Tibetan Mastiff.
Spots on the tongue are generally caused by deposits of extra pigment. These spots occur on parts or all of the tongue and also can occur on the dog's skin, though they are usually hidden by fur.