When most people think of a calico cat, they think of a patchy cat with white, orange, and black. This is generally true, although real cat people think of it as a cat that is white with black, and red (the way orange is referred to correctly among the feline crowd, although some people also call it ginger) patches. If a dilute gene is present the colors will appear muted and the cat will be white with gray and pale orange patches (also called blue and cream). In calicos the color patches are typically clear and well defined. In some areas calico cats are called tri-colored cats, or tortoiseshell with white.
photo source – Longhaired Calico Cat
A tortoiseshell shell cat is one without white. The black and red areas (or black and orange) tend to be more blended and hard to define. Often times the facial markings will be more clear, and opposite (with one side being black where the other side is orange). If the cat has some white on it the cat will be said to be tortoiseshell with white. This would usually be no more than a spot on the neck, or feet.
photo source - Tortoiseshell Cat
A torbie is a cat that is more like a calico but with the clear addition of the tabby (stripes) pattern. Many people will refer to torbie cats as calicos. The cat in the tortoishell picture (above) also has some tabby pattern, but is correctly called a tortoishell cat.
photo source – a Torbie Cat, she could also be called a Calico
These three cat color patterns, the calico, tortoiseshell, and torbie, are sex linked. Cat color is controlled by the X chromosome (which females have 2 and males have only 1). When any of these colors do show in a male cat the cat is very likely a chimera (the result of female embryo fusing with a male one early on in utero). Or else they are males with 2 X chromosomes and 1 Y chromosome.
Typically male cats who are calico, tortoiseshell, or torbie, are sterile, although this may not always be the case. They are no more likely to produce such rare colored offspring than any other cat, although people will often pay a high price for them.
Note: Calico, tortoiseshell, and torbie, are not breeds of cats, they are colors.
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