A calico cat is a domestic cat of any breed with a tri-color coat. The calico cat is most commonly thought of as being typically 25% to 75% white with large orange and black patches (or sometimes cream and grey patches); however, the calico cat can have any three colors in its pattern. They are almost exclusively female except under rare genetic conditions.

“Calico” refers only to a color pattern on the fur, from colorful printed Calico fabric, not to a cat breed or any reference to any other traits, such as its eyes.

Because genetic determination of coat colors in calico cats is linked to the X chromosome, calicos are nearly always female, with one color linked to the maternal X chromosome and a second color linked to the paternal X chromosome. In most cases, males are only one color (for instance, black) as they have only one X chromosome. Male calicoes can happen when a male cat has two X chromosomes (Klinefelter syndrome, with XXY sex chromosomes and generally sterile); is a chimera, with two different cell types; or, rarely, when some skin cells of the developing kitten spontaneously mutate.

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