What determines a cat’s colour?

The cats that share our homes and gardens come in a whole rainbow of colours. From black, white and grey to orange, brown and even blue. But have you ever wondered why they have so many different hues and patterns?

Our domestic cats all share one common ancestor, the African wildcat. They have been around for millions of years. In the wild, they have no need for variations in coat colour. It’s more important for them to blend in with their surroundings to avoid detection from predators and prey. When cats started to become domesticated in Ancient Egypt, around 4000 to 2000 BC, camouflage became less important. That's when different coat colours began to develop. For the last 200 years, selective breeding in cats, mostly for appearance, has become more common. This has led to the wide range of cat colours we see today.

These changes in coat colour occur from gene mutations that happens naturally in the cat’s cells. This has led to some interesting cat colour quirks…

Most ginger cats are male 

Roughly two thirds of ginger cats are male, and a third are female. The ginger colour comes from a gene mutation on the X chromosome. Because female cats have two X chromosomes it’s more unlikely that they would have the ginger gene mutation on both, although it’s not impossible. Male cats have one X and one Y chromosome. The Y chromosome doesn’t carry information about coat colour, so they only need one gene mutation to become ginger.

Nearly all tortoiseshell cats are female 

Female cats with a tortoiseshell pattern will have a ginger gene mutation on one X chromosome. Their other X chromosome will dictate the rest of their coat colour. Because males only have one X chromosome, they can usually only be either ginger or not ginger. They can't be a tortoiseshell pattern with patches of ginger. For a male cat to have a tortoiseshell pattern they would need to have an extra chromosome; two X chromosomes and a Y chromosome. This is extremely rare.

Deaf cats are more likely to be white 

Congenital deafness predominantly occurs in white cats. This is because the gene that causes a white coat can also be responsible for blue eyes and deafness. But there are other factors that can influence these variations. While not all white cats will be deaf, most cats that are congenitally deaf will be white and have two blue eyes.

All cats are tabbies 

The original cat coat is the striped or ‘mackerel’ tabby. The ‘blotched’ tabby pattern appeared later. Whether a cat shows their tabby pattern depends on whether they have inherited the recessive solid colour gene or not. Even kittens with this gene will sometimes show their tabby pattern when they’re young. They then shed their kitten coat when they become adults. Often an adult solid-colour cat in bright sunshine will have a faintly visible tabby pattern.

A mother cat can have kittens of different colours 

One litter of kittens can contain cats of all different colours, particularly if the mother has mated with more than one male. Male kittens will always inherit their colour from their mother. Whereas female kittens will be a combination of the colours of each parent.

Of course, here at Cats Protection, we believe that a cat’s personality is more important than their colour. This is why we encourage those looking for a new furry friend to consider cats of all colours.