Tortoise shell cat

Tortoiseshell is a cat coat coloringnamed for its similarity to tortoiseshellmaterial. Tortoiseshell cats are almost exclusively female.[1][2][3] Male tortoiseshells are rare and are usually sterile.[4][a]
Also called torties for short, tortoiseshell cats combine two colors other than white, either closely mixed or in larger patches.[2] The colors are often described as red and black, but the "red" patches can instead be orange, yellow, or cream,[2] and the "black" can instead be chocolate, grey, tabby, or blue.[2] Tortoiseshell cats with the tabby pattern as one of their colors are sometimes referred to as a torbie.[6]

"Tortoiseshell" is typically reserved for particolored cats with relatively small or no white markings. Those that are largely white with tortoiseshell patches are described as tricolor,[2] tortoiseshell-and-white (in the United Kingdom), or calico (in Canada and the United States).[7]

Tortoiseshell markings appear in many different breeds, as well as in non-purebred domestic cats.[7] This pattern is especially preferred in the Japanese Bobtail breed,[8] and exists in the Cornish Rex group.[9]Tortoiseshell cats have particolored coats with patches of various shades of red and black, and sometimes white. A tortoiseshell can also have splotches of orange or gold, but these colors are rarer on the breed.[4] The size of the patches can vary from a fine speckled pattern to large areas of color. 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; and the markings on tortoiseshell cats are usually asymmetrical.[10]

Occasionally tabby patterns of black and brown (eumelanistic) and red (phaeomelanistic) colors are also seen. These patched tabbies are often called a tortie-tabby, torbie or, with large white areas, a caliby.[10] Not uncommonly there will be a "split face" pattern with black on one side of the face and orange on the other, with a dividing line running down the bridge of the nose. Tortoiseshell coloring can also be expressed in the point pattern, referred to as a "tortie point".[10]