About 40 varieties, or breeds, of domestic cats are recognized internationally. Although the various cat breeds often differ dramatically in coat length and overall look, they vary less in size than do dog breeds. The smallest cat breeds weigh about 2 to 3 kg (about 5 to 7 lb) when full grown; the largest weigh about 7 to 9 kg (about 15 to 20 lb). So far, attempts to develop miniature or giant domestic cat breeds have been unsuccessful.
Many domestic cat breeds, including the Maine coon, Manx, Russian blue, and Siamese, began as a naturally-occurring variety of domestic cat native to a specific geographic area. Others, such as the Himalayan, are man-made breeds, the result of generations of careful breeding for a desired look. Some relatively new breeds, including the curly-coated Rex breeds, the hairless Sphynx, the fold-eared Scottish fold, and the curl-eared American curl, began with a genetic mutation and were then developed by selective breeding into a distinct breed.
For each domestic cat breed, there is an official standard of perfection registered with different cat associations that describes the ideal cat of that breed and its distinctive features; lists desirable and undesirable characteristics; and mentions faults that, in a cat show, could result in penalty or disqualification. For example, in the Siamese breed standard, the eyes are described as almond-shaped and slanting toward the nose; a tendency to squint is penalized, and crossed eyes are a disqualifying fault.
Breed standards differ slightly from cat association to cat association, and not all cat associations recognize every breed. To become recognized in a particular cat association, a breed must first be accepted for provisional status by that association. To become recognized for championship competition, the breed must complete a rigorous set of requirements that differ from association to association.
"Cat," Microsoft® Encarta® Online Encyclopedia 2003
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