Like other domesticated animals, there are different breeds of cat. Well-known breeds include the Siamese, Abyssinian, Manx, Persian, and Maine Coon. Cats began to be categorized into breeds in the 19th century with the advent of cat shows.
Today, there are over 100 cat breeds and varieties recognized by one or more of the official cat registries. Most pet cats, however, do not belong to any breed; they are random-bred, or just ordinary house cats of mixed breed.
What is a breed?
A breed is a type of domestic animal that is bred in a controlled way to produce offspring with consistent features. This holds true for most breeds of cat, but sometimes outcrossing (mating with another breed) is allowed for health reasons or to introduce or refine a feature such as the coat.
Cat breeds have been developed relatively recently. As cat fancy took off in the 19th century, registries were established to keep records of show cats and their genealogies. These registries define the characteristics, or “breed standards,” of each breed.
Major ones include the Cat Fanciers Association (CFA) and The International Cat Association (TICA), the Fédération Internationale Féline (FiFe), and the Governing Council of the Cat Fancy (GCCF).
Cat breeds are defined by their appearance: their coat—its color, pattern, and length; head and body shape; and eye color. Unusual features, such as absence of tail, short legs, and folded ears, also define certain breeds.
Coat colors and patterns are particularly varied, with some breeds, such as the Chartreux, having just one color, and others, such as the British Shorthair, being permitted many coat colors and patterns.
How breeds develop
Some breeds, such as the British Shorthair, developed naturally from isolated groups of cats, their restricted gene pool resulting in a typical appearance. Other natural breeds arose because they had a characteristic that helped them survive, such as the long coat of the Maine Coon, which is indispensable for cold, northern winters.
In small, isolated populations, a trait caused by a genetic mutation—which would probably only rarely appear in a larger population—can become common over generations of inbreeding.
This genetic influence is called the “founder effect” and accounts for the taillessness of the Manx, for example. Breeders exploit the founder effect to create new breeds from cats with novel characteristics caused by a mutation. Such breeds include the Scottish Fold, Munchkin and Sphynx.
The role of genetics
Breeders of pedigree cats use their understanding of genetics to pinpoint characteristics that are caused by dominant or recessive genes. They can then predict how the offspring of different parents will look. Dominant genes require just one copy from either parent to produce an effect.
For example, the gene that produces a tabby coat is dominant over the gene causing a non-tabby coat. Recessive genes need two copies—one from each parent—to have an effect. Long hair is another recessive characteristic.
Cat registries stipulate in their breed standards what outcrosses, if any, are permissible for each breed. Crossbred kittens are registered according to their appearance. Outcrossing is also used to develop new breeds, such as longhaired versions of shorthaired breeds.
Outcrossing is also necessary for the health of certain breeds; for example, Scottish Folds are usually a cross between a Fold and a British or American Shorthair with normal ears. This pairing keeps kittens from receiving two copies of the fold mutation, because such kittens suffer from a debilitating disease affecting bone development.
Hybrids and future breeds
In recent decades, domestic cats have been crossed with other species of small wildcats to create new breeds, usually with striking “exotic” coats. These hybrids include the Bengal, Chausie, and the Savannah.
New breeds—arising purely from other domestic cats—are always being developed, but it can take years for them to be accepted by cat registries. Pipeline breeds include the Arctic Curl—a shaggy-haired cross between the Selkirk Rex and the Angora—and the Benedictine, a longhaired Chartreux with DNA from the Persian.