The answer to why do calico cats have three colors is very interesting. Calico cats (sometime called tortoiseshell-and-white) result from a specific gene combination normally only occurring in female cats. It is not a breed but a condition that can occur in a number of breeds. Some breeds officially allow this coloration including American Shorthair, British Shorthair, Exotic Shorthair, Manx, Turkish Van and Persian.
To quote from The Genetics of Calico Cats (which gives a full technical description for those interested):
“Normal female mammals have two X chromosomes. Normal males have one X and one Y chromosome.”
To describe it simply the X chromosome has a gene that can either produce a red coat or a black coat. In a male there is only one so the cat will be either red or black. Many females will also be one color or the other because they will either have two black genes or two red. When they have one of each, they are tortoiseshell.
The random patchwork of color on the tortoiseshell is due to a process called lyonization in which one of the genes (black or red) comes to determine the color for each individual cell. That gives us the two colors of the Calico’s three.
Next we need a splash of white on the tortoiseshell to produce a calico. White fur has no pigmentation and caused by a specific piebalding gene. Some experts think that there may be more than one gene causing this condition (for example the gloves on the Birman cat). In fact, piebalding itself is a fascinating, and as yet not fully understood, subject. The extent of piebalding may vary widely.
Why Do Calico Cats Have Three Colors: The Result of the Above Produces—
We know this kitten is a girl but is it ever possible to produce a boy with a coat like this? Surprisingly they can. Just like a small number of men have an XXY gene so do some male cats. Because of the double X gene the male can be calico just like a female. These are however very rare and normally infertile.
Why do calico cats have three colors? Its really a tortoiseshell with piebalding: two genetic factors combined. If you enjoyed this post please share it with you friends.