Tortoiseshell cat

Tortoiseshell is a coloring found in

eumelanin

based color (black, chocolate and cinnamon).

Patterns

The mix of colors results in a cat with patches of red and patches of black, chocolate or cinnamon. The size of the patches can vary from a fine speckled pattern to large areas of colour. Typically, the more white a cat has, the more solid the patches of color. Dilution genes may modify the coloring, lightening the fur to a mix of cream and blue, lilac or fawn. Occasionally brown or blue/grey

breeds of cat

. The tortoiseshell markings appear in many different breeds.

Coat Color Genetics

Coat coloration in cats is complex, and controlled by several genes. One gene involved has two alleles: the Orange allele, O, which is the dominant form, (i.e., XO), and produces orange fur; and the "Black" allele, "o", which is the recessive form, (i.e., Xo), and produces black fur.

For a cat to be calico, it must simultaneously express both of the alleles, O and o, which are two versions of the same gene, located at the same location on the

Klinefelter's syndrome, carrying an extra X chromosome, and will almost always be sterile or they may be a chimera

resulting from the fusion of two differently coloured embryos.

The spotting gene causes white patches to cover the colored fur. Although there is no genetic difference, the amount of white is artificially divided into mitted, bicolour, harlequin, and van, going from almost no white to almost completely white.

In normal female tortoiseshell cats and in Klinefelter males, the position of the patches depends on which X-chromosome is active in each cell and which is inactivated to become a Barr body.

The Calico Cat is the
state cat of Maryland
.

They are almost always female.

They are said to be very temperamental (a generality disputed by some calico owners).

Myths say calicos bring luck in Asia and bring health in Scotland.

Tortoiseshell cats are often called torties.

Gallery of Tortie Types

A calico cat
A tortie cat

A tortie cat
A tortoiseshell cat
A blue/dilute tortoiseshell cat

A blue/dilute tortoiseshell cat
A short-haired blue/dilute tortoiseshell

A short-haired blue/dilute tortoiseshell
An orange and black tortoiseshell medium-haired female
A calico cat
Tortie in the sun
Calico at Christmas
A calico cat

A calico cat
A calico cat

A calico cat
A "torbi" kitten
A calico cat

A calico cat
A long-haired tortoiseshell cat
A tortoiseshell-point Siamese cat
A calico cat