Tortoiseshell cat

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(Redirected from Calico cat)

Tortoiseshell is a coloring found in cats caused by a combination of specific genetic traits. It is a mix of phaeomelanin based colors (red) and eumelanin based color (black, chocolate and cinnamon). The pattern 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. Dilution genes may modify the coloring, lightening the fur to a mix of cream and blue, lilac or fawn. Occasionally silver or ginger tabby patterns are also seen (sometimes called "torbies"). Tortoiseshell also can be expressed in the points pattern. The description "tortoiseshell" (also called "calimanco" or "clouded tiger" in North America) is correctly reserved for cats with coats that have no white markings, while those that are largely white with orange and black patches are described as calico (in the US) or tortoiseshell-and-white (in the UK). Tortoiseshells and calicos are not specific breeds of cat. The tortoiseshell markings appear in many different breeds.

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 X chromosome. Males normally cannot do this: they can have only one allele, as they have only one X chromosome. Over 90% of tortoiseshell cats are females. Occasionally a male calico is born. These may have 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.

A Blue/Dilute "Tortie" cat	Three-month-old Kaka	A Calico cat, which is a tortoiseshell	A tortoiseshell-and-white (calico) cat
A tortie cat named Chelsea	Cosmo, a tortoiseshell kitten	Long-haired tortoiseshell cat Clio	A tortoiseshell cat
A tortoiseshell-point Siamese cat	Honey, A short-haired tortoiseshell Calico	Short-haired tortoiseshell-and-white cat named Xena	Orange and black tortoiseshell medium-haired female