Dog types are broad categories of dogs based on function; dog types are not identical to modern dog breeds but dogs identified primarily by specific function or style of work rather than by lineage or appearance, including ancestral forms (or landraces) that arose undocumented over a long period of time.
The terms dog breed and dog type are sometimes used interchangeably, but they have different meanings. A modern dog breed is standardized, with a documented descent from known ancestors. All members of a modern dog breed closely resemble each other, while dogs raised and trained for a specific working ability rather than appearance may not closely resemble other dogs doing the same work, or any of the dogs of the analogous breed group of purebred dogs.
With the beginnings of agriculture, approximately 12,000 years ago, humans began making use of dogs in various ways. Molecular biologist and founder of the Canine Genome Project Elaine Ostrander comments, "When we became an agricultural society, what we needed dogs for changed enormously, and a further and irrevocable division [between dogs and wolves] occurred at that point. There is a great deal of speculation about the early uses of dogs, but recent genetic analysis shows that the earliest ancestors of modern breeds (those with the least genetic divergence from the ancestral wolf) include lap dog types (Pekingese, Shih Tzu) along with hunting dog and working dog types.
Almost one hundred years later, another book was published in English, De Canibus Britannicus, translated from Latin in 1576. The author, John Caius, described types of dogs in four main categories: hunting dogs, lap dogs, farm dogs, and mongrels. Sub-types describing the function of dogs in each group were also included.
In 1758, Carl Linnaeus in Systema naturae named the domestic dog “familiaris” and added other dog species. More dog types were described as species by Johann Friedrich Gmelin in 1888, and by Robert Kerr in his English translation of Systema naturae (The Animal Kingdom) in 1792. Today the species Linnaeus named are identifiable as dog types, not species or subspecies. Some, such as Canis aegyptius, a hairless dog type of Peru, have been documented and registered as breeds (Peruvian Hairless Dog). There are only two categories (subspecies) of domestic dog, Canis lupus familiaris and C. l. dingo, recognized by the International Code of Zoological Nomenclature (ICZN Code).
Beginning with the advent of dog shows in the mid-1800s in England, dog fanciers established stud books and began refining breeds from the various types of dogs in use.
At the beginning of the 1800s there were only a few dogs identified as breeds, but when dog fighting was outlawed in England in 1835, a new sport of dog showing begain. Along with this sport came rules and written records and closed stud books. Some of the old types no longer needed for work (such as the wolfhound) were remade and kept from extinction as show dogs, and other old types were refined into many new breeds. Sometimes multiple new breeds might be born in the same littler of puppies. In 1873 only 40 breeds and varieties were known; today there are many hundreds of breeds, some 400 are recognized by the Fédération Cynologique Internationale.
Dog types today are recognized in the names of Group or Section categories of dog breed registries. But dog types have not disappeared. Types of feral dogs are being discovered and registered as breeds, as with the New Guinea Singing Dog and Carolina Dog. Types re-emerge from mixes of breeds, like the Longdogs from Lurchers and Greyhounds. Named types of dogs that are not dog breeds are still being used where function or use is more important than appearance, especially for herding or hunting, as with the herding dog types of New Zealand that are described by their exact function (Heading Dog, Huntaway, Stopping Dog, etc. - functional terms, not necessarily breed names).
note 2. Presumed to be of older lineage are modern dog breeds Shiba Inu, Chow Chow, Alaskan Malamute, Basenji, Shar Pei, Siberian Husky, Afghan Hound, Saluki, Tibetan Terrier, Lhasa Apso, Samoyed, Pekingese, and Shih Tzu.
note 3. Dog types in use in 1486: Grehoun, Bastard, Mengrell, Mastiff, Lemor, Spanyel, Raches, Kenettyes, Teroures, Butchers’ Houndes, Myddyng dogges, Tryndel taylles, Prikherid currys, and smalle ladyes’ poppees. Some of these dog types are still identifiable today.
note 4. Many modern breeds of dogs still use the names of early types, although they may or may not resemble the old types.
note 5. Early attempts to catagorize dogs as species (not actually species, today considered dog types) of Canis are described by Carl Linnaeus in Systema naturae, 1758, Gmelin in1788, Kerr in 1792.