Many variations have occurred in the fur types of domestic cats, some having evolved naturally, while others have been produced by selective breeding. Fur type is an individual feature of each breed, independent of color, and is determined by the specific combination of down, awn, and guard hairs in the fur. Guard, otherwsie known as primary hairs, constitute the longest and the most visible part of the coat. Down are short and soft hairs that help provide body insulation. Some breeds lack down hair. Awn are slightly longer, bristly hair that, together with the short down hair, constitute the secondary hairs.
Coat length can be variable, depending on the breed and the season; the density of the coat results largely from the down hair which also provides the greatest insulation. The Persian longhair has long guard hairs protruding through the thick down hairs, creating a very dense coat. The hairs of the Angora are finer and less profuse, while the shaggy appearance of the Maine Coon results from the uneven lengths of the individual guard hairs.
There is considerable variation in both the appearance and texture of the coats of this group of cats. The Siamese and the Oriental cats have sleek, short coats, with very soft, fine-textured hairs. By contrast, the Manx has a pronounced double coat. The Russian Blue is another breed that has a very distinctive double coat; this stands up, away from the body, and is soft and silky in texture, as well as being short and thick.
This description is used for cats that have a fairly long topcoat and a greatly reduced uncercoat, compaired with either Persians or Himalayans. Included in the semilonghair group are breeds like the Main Coon that have evolved naturally. These breeds usually show a difference in coat length between winter and summer.
The "Hairless" Sphynx
In spite of the name, the Sphynx does have some hair, most visible on the extremeties. It also has eyebrows and whiskers, but these are usually shorter than normal. Most of the body has a light covering of down hairs.