The domestic short-haired cat is of mixed ancestry that does not belong to a recognized cat breed. In the cat fancy, such cats are designated Domestic Shorthair (DSH), a pseudo-breed, for registry classification purposes (uncommonly, some such cats are actually pedigreed). Domestic short-haired cats should not be confused with the British Shorthair, American Shorthair or other breeds with “Shorthair” names, which are breeds recognized by various registries. In British English, they are often referred to as moggies.
Domestic short-haired cats are characterized by a wide range of coloring and typically “revert to type” after a few generations, which means they express their coats as a tabby cat. This can be any color or combination of colors. They also exhibit a wide range of physical characteristics and, as a result, domestic short-haired cats in different countries tend to look different in body shape and size, as they are working from differing gene pools. DSH cats in Asia tend to have a build similar to a purebred Siamese cat or Tonkinese cat, while European and American varieties have a thicker, heavier build. DSH cats have a form of hybrid vigor due to their diverse gene pool, so that they are much less vulnerable to the genetic problems for which purebred cats must be carefully screened