It is impossible to know exactly when the first Bristol cat was bred. It is also difficult to be sure of the ancestry of the first Bristol cats. They do resemble the Bengal, but only to a certain degree, and it is thought that the Bristol actually predates the Bengal by many years. If this is the case, it is unlikely that the Bristol is a variation of the Bengal. Due to its exotic nature, it is rather more likely that the Bristol is a cross between the American Shorthair and the margay.
These cats tend to resemble an orange ocicat. Some have a smoky charcoal appearance, which is unlike a Bengal, while others had white or pale bellies and legs. They also had margay-type rosettes, an ocelot-like voice, and small, rounded ears. The ears, which are unlike their American Shorthair ancestors, are certainly an indication that a non-domestic cat is the other parent.
In 1991, some of these cats were found at a private residence in Texas. These cats were once registered with TICA as “Bristol Cats.” However, their chronic infertility had caused TICA to drop the breed many years before. Indeed, the cats in Texas, though beautiful and affectionate, were not very fertile. These cats had several characteristics that were definitely not of domestic origins, such as the ears, pattern, color, and head shape. While documentation of these cats remains unproven, experts do believe that these cats were a result of crossing domestic shorthairs or American Shorthairs with the wild margay.
Today, the margay and the American Shorthair are occasionally bred to create this interesting crossbreed. Considered designer cats, the Bristol cannot be thought of a true breed. This is because one of the defining characteristics of a breed is the fertility of the offspring. However, the American Shorthair-margay cross produces kittens of limited fertility. When these kittens are successfully bred together (which occurs only rarely), they do not appear to produce kittens with noticeable or sustained fertility.
These cats are considered rare and are sought after by those who can find a breeder and are willing to pay the high price tag.
First published at Helium, http://www.helium.com/items/2112174-bristol-cat-breed