Tortoiseshell cats, with their colorful woven coats, provide a veritable feast of colors. Because of the resemblance to the fallen leaves of autumn, we at About.com have traditionally celebrated "torties" in our November Cats Picture Calendar Gallery.
It's All in the Genes
Tortoiseshell cats are basically two colors: red and black, along with variations aka "dilutes" of those colors: lighter shades of red (creams), and lighter shades of black (blues, pale grays), and browns. Torties also come in two types of color patterns: "brindled" (woven) and "patched"(solid patches of red or black, (or dilutes of these colors). To make it even more complex, these patches may also be of the tabby nature, resulting in what is often called "Torbies."Tortie and White
Add white patches to the tortoiseshell mix, and you have a "tortie and white," also known as "calico." My own way of separating the varieties is that calicoes are white with scattered patches of red and black. If the patches are woven, I'd call them "tortie and white." It's all academic anyway, because all calicoes are torties, while not all torties are calicoes.
The Sex Quotient in Tortoiseshells
As if the above isn't complex enough, the O gene makes its entrance. According to Sarah Hartwell, of the esteemed messybeast.com:- "The ginger colour of cats (known as "yellow", "orange" or "red" to cat breeders) is caused by the "O" gene. The O gene changes black pigment into a reddish pigment. The O gene is carried on the X chromosome. A normal male cat has XY genetic makeup; he only needs to inherit one O gene for him to be a ginger cat. A normal female is XX genetic makeup. She must inherit two O genes to be a ginger cat. If she inherits only one O gene, she will be tortoiseshell. The O gene is called a sex-linked gene because it is carried on a sex chromosome. Tortoiseshell cats are therefore heterozygous (not true-breeding) for red colour."
The "Tortitude" Factor
Tortoiseshell cats share a unique personality most often described as "tortitude." Torties are almost always very active and playful, with sassy, spunky, in-your-face attitudes. They also often fancy themselves as alpha cats, which can sometimes create problems Calicoes also exhibit definite tortitude in their personalities. I can't help but think that this personality trait has its origin in genetics, as opposed to environment.It should also be noted that torties can be very affectionate and loving, even though some of them may not want to be held for long. If you want to find your way into a tortie's heart, pet her when she asks, play with her as often as possible, and be grateful whenever she finds her way into your arms.
