Last Updated on January 7, 2021 by Julia Wilson
What is a calico cat?
Calico is a common coat pattern which occurs almost exclusively in female cats and consists of a white base (25-70%) with patches of red and black, red and grey or red and brown. Calicos are not a breed, the word calico refers to the coat colour only, and calico can be found in both random-bred and purebred cats.
The calico is also known as tricolour or tortie and white outside the United States of America.
How does the calico coat pattern occur?
There are four base (solid) colours in cats:
Why not white? Because a cat with a coloured and white coat (calico or bi-colour) has a gene which switches off colour in some parts. The gene responsible is known as piebald or spotting gene (abbreviated to S) and is dominant, as signified by the uppercase S. This means a bi-colour or calico cat is genetically a coloured cat, but the S gene has switched off the colour in certain areas.
Male calico cats
Only 1/3,000 calico or tortoiseshell cats are male. To understand why calicos are so rare in male cats, we need a basic understanding of genetics.
The red gene:
The red (actually known as orange and abbreviated to O) gene is only carried on the X chromosome, which makes it sex-linked. The O gene is dominant (all dominant genes are abbreviated in UPPER CASE, all recessive are lower case). The mother’s eggs only carry an X chromosome, but the male sperm can carry either an X or a Y chromosome. Each cat will inherit an X from their mother and an X or Y from the father.
- Female – XX (X from the mother, X from the father)
- Male – XY (X from the mother, Y from the father)
Interestingly, the faulty gene for hemophilia, a blood clotting disorder, is also sex-linked and found on the X chromosome. Because females have two chromosomes, the good one prevents her from developing the condition, however as the male-only has one X chromosome, he will develop hemophilia. This is the same for colour blindness in human males too.
Female = XX
Male = XY
As the male cat only has one X chromosome, if it carries the O gene (which remember, is dominant), then he will be an orange/red male. If the X chromosome carries the o (non-orange) gene, then the male will be another colour, usually black.
If however, the female kitten inherits both the O and the o (usually black) gene, then because she has two X chromosomes (instead of an X and a Y like the male), both black and red will show making a tortoiseshell cat. If she also inherits the white spotting gene which is responsible for the white coat colour, she will be black, red and have areas of white.
I like to think of the X chromosome as having four sections (or arms), and the shorter and smaller Y only has three. The extra arm the X chromosome contains additional genes including the O gene. Most genes (except for the sex-linked X and Y) come in two pairs, one from the mother and one from the father. Therefore the male cat only inherits one O gene (which is dominant) from the X chromosome from his mother.
The male cat only needs one copy of the O gene to be a red cat; however, the female needs two copies of the O gene to be red, which is why female ginger cats are seen less often than males.
For the female inheriting the red and black genes from both parents, the following may occur:
- O (from mother) O (from father) OO=Ginger cat
- o (from mother) o (from father) oo=Black cat
- O (from mother or father) o (from mother or father) Oo=Tortie cat
In the male cat, orange is dominant over black, so if he inherits one O gene and one o (non-orange) gene, he will be orange. So the following will occur:
- O (from mother or father) o (from mother or father Oo=Ginger cat
- 0 (from mother) o (from father) oo=Black cat
Why are females black and orange?
Females carry two X chromosomes (one from each parent), a process known as x-inactivation or Lyonization occurs during fetal development. Every cell has one active and one silenced X chromosome, this includes the melanocytes, which are the cells responsible for hair colour. Therefore the information contained in the active X chromosome is used, and the information in the silenced X chromosome isn’t, this results in both male and females only have one X (active) chromosome per cell.
As this happens in the female carrying both orange and black, the random nature of inactivation means both red and black can appear in the coat depending on which X chromosome has been inactivated in the cell.
Just to complicate things more, the calico cat is essentially a tortoiseshell cat with the addition of the piebald (spotting) gene, this gene turns parts of the coat white by switching off the colours in some areas.
Calico coat colours
Black or brown with red and white are the most common calico colour combinations.
Dilute calico cats
Some cats carry the dilution gene causes clumping and an uneven distribution of the pigment granules in the hair shaft, producing a dilution of the coat colours which changes black to grey (blue) or and orange to cream.
The dilute modifier gene caramelises the coat colour of dilute cats who carry the gene.
The chart below shows the effects of the dilution and the dilute modifier genes on the coat colours.
|Black (brown)||Blue (silver)
Are calico cats sterile?
We already know that calicos are almost always female cats, and they are as fertile. It is very rare for a male to be calico when he is; he is almost always sterile.
Male calico cats
We know that for a cat to have a calico cat, two X chromosomes are necessary, and the male has one. So how is it possible that some male cats are calico?
- Klinefelter syndrome: The male inherits an extra X chromosome due to an error during meiosis, which is the division of parent cells to produce sex cells.
- Chimera cats: If two recently fertilised eggs (XX and XY) which have fused, meaning there is one cat, but it has two distinct sets of DNA. This makes him a chimera.
- Mosaics: One fertilised egg develops into two distinct cell lines due to a random error in a cell of the developing embryo.
Breeds of cat which can come in calico
The most common type of calico cat is the domestic, or moggy. However, it can be found in some pure breeds of cat too.
- American Bobtail
- American Curl
- American Shorthair
- American Wirehair
- British Shorthair
- Cornish Rex
- Devon Rex
- Japanese Bobtail
- Devon Rex
- German Rex
- Maine Coon
- Norwegian Forest Cat
- Scottish Fold
- Scottish Shorthair
Official state cat of Maryland
The calico has been the Maryland State cat since 1st October 2001. Calico cats were chosen because their orange, black and white colouring resembles the colouring of the Baltimore oriole, a state bird and the Baltimore checkerspot butterfly, the state insect.
Calico cat FAQ
Where does the name calico come from?
Calico is taken from a fabric with the same name which originated in Calicut, (from which the name of the textile came) in southwestern India.
How to pronounce calico
Are calico cats talkative?
As calico is a colour and not a breed which many have specific traits, each calico cat will vary.
What is a calico cat personality?
Again, this will vary from cat to cat. A calico cat who has been kept with her mother until ten weeks and had plenty of human contact during this time will generally be friendly and get along with people.
What is the difference between a calico cat and a tortoiseshell (tortie) cat?
A tortoiseshell cat is black or brown, and orange and are often mottled, a calico also has patches of white. Read here for more information.
What is the name of a calico cat with tabby markings?
A calico-patched tabby is called a caliby.
Are calico cats lucky?
Calico cats are associated with the Maneki Neko (also referred to as Lucky cats, Money Cats or Beckoning cat) which is placed in the doorway of businesses and homes to bring good luck and fortune.
Do calico cats have health problems?
Female calico cats are as healthy as any other coat colour, however, male cats with Klinefelter’s syndrome (XXY) can have health issues associated with their condition.
Are calico cats chimeras?
It is possible that a male calico is a chimera, meaning the cat carries two distinct genotypes. We know that identical twins occur when one fertilised egg splits and develops into two babies, who share almost identical genetic profiles. In chimera cats, two non-identical fertilised eggs merge into one during early development which results in a cat with two different cell lines in the one body.
Are calico cats expensive?
No, the calico is no more expensive than any other cat. Male calico cats are rare, however, they do not attract a higher price tag than female calico cats.
Calico cat lifespan
The lifespan of the calico is between 12-14 years for an indoor cat.
Calico cat names