Posted on Wednesday, May 2nd, 2012

Unique beauty: The Tortoiseshell Cat

Tortoiseshell Cat

Tortoiseshell cats are named for their distinctive coloring – a combination of patches of black, brown, amber, red, cinnamon and chocolate.  The size of the patches varies from a fine speckled pattern to large areas of color.  The term “tortoiseshell” is used for cats with brindled coats that have few or no white markings.  Cats of this coloring with larger areas of white fur are called calicos. Sometimes, these colors present in lighter versions such as lilac or cream.  Torties with this lighter coloring are called dilute torties.  Occasionally, the typical tortoiseshell colors are also seen in a tabby (striped) pattern, and these cats are sometimes referred to as “torbies.”

Tortoiseshell cats are almost exclusively female.  Tortoiseshell and calico coats are the result of the interaction between genetic and developmental factors.  The occasional and very rare male tortoiseshell cat is the result of a genetic mutation.

The Science behind the beauty
The ginger color 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.

In order to produce tortoiseshell kittens, at least one of the parents must carry the O gene. Red male and red female only produce red kittens. The combinations which produce tortoiseshell kittens are red male and non-red female, red female and non-red male. The following can also produce tortoiseshell kittens: tortie female and non-red male, tortie female and red male. It also depends on some kittens being female.

Odd science behind the beauty
This may seem an odd topic, but if you clone a tortoiseshell cat you will end up with a cat of one or other of the constituent colors and not a tortoiseshell clone. If you clone a red/black tortoiseshell, the clone will be either red (ginger) or black.

Whatever the science behind these cats, one thing is for sure, they are beautiful! Have you ever seen a tortoiseshell cat?