The American Staffordshire Terrier also known as Amstaff is a medium-sized, short-coated American dog breed.
In some cases, a breed's origin overlaps the boundaries of two or more countries; the dog is normally listed only in the country with which it is most commonly associated (for example, by its designated country according to the Fédération Cynologique Internationale (FCI).
The basic types are companion dogs, guard dogs, hunting dogs, herding dogs, and working dogs, although there are many other types and subtypes.
As such, dogs are the only animal with such a wide variation in appearance without speciation, "from the Chihuahua to the Great Dane". The following list uses a wide interpretation of "breed".