Cats come in a kaleidoscope of colours - sometimes all in the one litter, and among the most popular (and some owners would say the most attractive) are tortoiseshell and gingers. Tortoiseshell cats are considered lucky in Scotland and Ireland.

Tortoiseshell cats are a patchwork of black and orange in a random pattern. When tortoiseshells have white markings they are sometimes also known as calico cats.

Most tortoiseshell and calico cats are female. The gene for the red colour (O) is carried on the X chromosome and for this reason it is called a 'sex linked' colour. Females of all species have two X chromosomes and males an X and Y chromosome. If both X chromosomes carry the Red gene, then the cat will be Red. However, many females carry the Red gene on only one chromosome, which allows the blackbased pigmentation to show through in patches. This combination of red and black is called tortoiseshell. For a male to be a tortoiseshell, he must have a genetic mutation that causes the male to have two X and one Y chromosome that usually renders male tortoiseshell cats sterile. It is estimated that only one in about every 1,000 torties is male and that only one in 10,000 is fertile.

However normal males normally only have one X chromosome and so if a male carries the Red gene at all, he will be ginger.

It is possible to have a ginger female but since males only need to have the orange gene on one chromosome to become ginger, and females have to have it on two, ginger males outnumber females 3 to 1.

Mating together a red male and a red female can never give a tortoiseshell because the cats can only pass on the "O" genes to their kittens.

Tortoiseshell cats are fondly called 'torties' and are renown for their independent and resilient nature, although some people more unkindly call them temperamental! Perhaps their individual nature mimics their individual coat colour as no two torties will be identical in markings.

Famous ginger cats

• Garfield - the cartoon cat
  
• Ginger from the Beatrix Potter story Ginger and Pickles
  
• Jonesy - the orange cat in Alian
  
• Orangey - a film and television star. Orangey won the Patsy Award for animal actors in 1952 and 1962. Orangey also appeared in Breakfast at Tiffany's.
  
• Lucky - rescued from a cat shelter and renamed Morris and became a TV star in USA.
  

Famous tortoiseshell cats

• Catarina owned by author Edgar Allen Poe
  
• Selima - a tortoiseshell tabby owned by Horace Walpole (1717-1797) who made the Grand Tour of Europe with his friend the poet Thomas Grey, and when his beloved Selima was drowned in a goldfish bowl, Gray wrote a poem Ode on the Death of a Favourite Cat Drowned in a Tub of Gold Fishes
  
• Towser - (1963-1987) holds the record for the champion mouser of all time. Owned by Glenturret Distillery in Scotland, she is reported to have killed an average of three mice a day, every day of her adult life, giving an estimated total of 28,899!