Why most calico cats are female?

If you are like me, then you will probably be surprised to hear that the vas majority of calico cats are female. Ok…to begin, I will explain what a calico cat is, as not many know. A calico cat is not a breed of cat, it is a color pattern. To be called "calico", three colors must be present: black, white and orange. Variations of these colors include gray, cream and ginger. A "true" calico cat has large blocks of these three colors, a "tortoise shell" or "tortie" cat has a mix of these three colors (blended/swirled together more than distinct blocks of color).

Now that we cleared that a calico cat is a cat with three colors, the question is: why are they nearly always female? The answer is in genetics. Coat color in cats is a sex-linked trait, a physical characteristic (coat color) related to gender. Female animals have two X chromosomes (XX), males have one X chromosome and one Y chromosome (XY). The genetic coding for displaying black or orange color is found on the X chromosome. The coding for white is a completely separate gene. Since females have two X chromosomes, they are able to "display" two colors (orange and black, or variations thereof) and white; creating the 3-color calico mix. Since males have only one X chromosome, they can only be orange OR black. It is more complicated than simply having the color genes -- it is a complex process of dominant and non-dominate genes interacting on the X chromosomes, but that is the basis for coat color in calico cats. Can a calico cat ever be male? Yes, in rare instances. In this situation, the cat has two X chromosomes and one Y chromosome (XXY). Cats with this chromosomal configuration are usually sterile (not able to breed). This is similar to a condition in humans called Klinefelter's syndrome, or XXY Syndrome.

I must admit that this is too scientific, but it is how feline experts say, so, we might as well enjoy the fact that we finally know a calico cat is, and why most of them are female. I will finish with a fun fact about the calico cats: on the 1’st of October 2001, the calico cat became the official cat of the state of Maryland in the United States.