I often hear people describe their cat as a “Calico cat” like one would say I have a Siamese cat. But did you know, that the Calico is not a breed of cat, but the colour pattern of it’s fur? To be called “calico”, three colours must be present: black, white and orange. Another interesting fact is that approximately one calico in 3,000 is male. So, if you see a Calico cat, you can almost be assured that it will be a female cat.
A similar cat to Calico’s is the Tortoiseshell or Torties for short. The term “tortoiseshell” is used for cats with brindled coats that have few or no white markings. They also have a distinctive combination of bi colours of either black, amber, red, cinnamon or chocolate. The size of the patches varies from a fine speckled or brindle to large patches of colour. Sometimes, these colours present in lighter versions such as lilac or cream. Torties with this lighter colouring are called dilute Torties.
Tortoiseshell cats are almost exclusively female as well. Tortoiseshell and calico coats are the results of the interaction between genetic and developmental factors. The occasional and very rare male tortoiseshell cat is the result of a genetic mutation.
So why are these cats like this?
The answer is in their genetics. Coat colour in cats is a sex-linked trait, a physical characteristic (coat colour) related to gender. So, for the females they have two X chromosomes (XX), males have one X and one Y chromosome (XY). The genetic coding for displaying black or orange colour is found on the X chromosome. The coding for white is a completely separate gene. In female’s, one of the X chromosomes is randomly deactivated in each cell. For calico cats, the random mix of colour genes that are “on” or “off” gives the blotchy orange and black colour display.
In Other Words…
Since females have two X chromosomes, they can “display” two different colours orange or black and white; creating the 3-colour calico mix. Since males have only one X chromosome, they only have one black or orange gene and can only display orange or black.
And then there is this!
In addition to their distinctive colouring, Torties and Calico’s also have a reputation for unique personalities, sometimes referred to as “catitude.” They tend to be strong-willed, a bit hot-tempered, and they can be very possessive of their human. Other words used to describe them are fiercely independent, feisty and unpredictable. They’re usually very talkative and make their presence and needs to be known with anything from a hiss to a meow to a strong purr. These traits are stronger in tortoiseshell cats than in calicos – it seems as though these traits are somewhat diluted with the addition of more white to the colour scheme.
Written by Baxter Animal Hospital