What makes a cat calico?

A calico cat is a female cat with a tri-color coat: black, white, and orange (or cream). The specific color pattern can vary widely, but it's the combination of these three colors that defines a calico.

Here's what makes a cat calico:

* Genetics: Calico coloring is determined by a gene on the X chromosome. Females have two X chromosomes, while males have one X and one Y chromosome. The gene for calico coloring has two main alleles: one for black/orange and one for white.

* X Chromosome Inactivation: During embryonic development, one X chromosome in each cell of a female cat is randomly inactivated. This is called X-chromosome inactivation.

* Patchwork Pattern: If a female cat inherits different alleles for the calico gene on her two X chromosomes, the inactivation of one chromosome or the other in different cells leads to the patchwork pattern of black, white, and orange fur.

* Male Calicos: Male calicos are extremely rare. This is because they would need to inherit two X chromosomes (XX), usually due to a genetic condition called Klinefelter syndrome.

Important Note: While the combination of black, white, and orange is the defining characteristic of a calico cat, some people use the term "calico" to describe cats with any three-color coat pattern, regardless of the specific colors.