Categories: white

Why are domestic cats white?

The question effectively asks why cats are white all over. It is because they have a dominant gene symbolised by the letter W which removes pigment from the hair strands. It does this by removing the pigment creating cells in the skin. These are called melanocytes. Genes are on chromosomes and chromosomes are in the DNA of cats. The DNA is in the nucleus of the cells of the cat.

Genes instruct how cells are created during the embryonic stage of development of all animals. They determine all aspects of an animal’s characteristics including hair colour. So, for example, a human has blond hair because of the hair colour gene, known as MCIR.

Photo of White Snow + White Cat II by ace-of-finland on DeviantArt.

The gene masks all other colours (epistatic – the suppression of the effect of one such gene by another). The dominant white gene as it is called is present at a separate locus to the piebald gene (white spotting gene) and therefore not dependent on the piebald gene (i.e it is not an allele of the piebald gene).

The dominant white gene can also make cats deaf and the eyes are often blue (without iris pigment) or odd-eye colour (different coloured eyes, one blue and one yellow).

Odd-eyed white Scottish Fold living in St Petersburg, Russia. Photo: Caters.

A survey of 185 white cats found that 25% had yellow eyes and normal hearing, 31% had blue eyes and normal hearing, 7% yellow eyes and were deaf and 37% had blue eyes and were deaf. The deafness is “associated with degenerative changes in the succule and cochlea” (Robinson’s Genetics).

Partly white cats

Chocolate confection cat. Picture in public domain. The piebald gene produced the white areas of fur.

If the question was asking why cats have some white in their coats, it is because they have the piebald or white spotting gene. The classic cats which have the piebald gene are bicolour cats – white and another colour. However, there are millions of variations and other coats where areas of white fur are seen caused by the presence of this gene in the cat’s DNA (i.e. “lockets” on the chest and “gloving” on the lower leg). Breeders or geneticists grade the variations of expression of the gene from 1 to 10 where 2 is a near black cat with small spots of white and 9 is a near white cat with small spots of black.


In short the answer to the question in the title is “because of genes”.

P.S. Dalmatian dogs are bicolored. They too can be deaf. There are multiple causes the Kennel Club says. I’ll add my thoughts: the piebald gene is the cause or a contributing factor.

Michael Broad

Hi, I'm a 71-year-old retired solicitor (attorney in the US). Before qualifying I worked in many jobs including professional photography. I have a girlfriend, Michelle. I love nature, cats and all animals. I am concerned about their welfare.

Recent Posts

Are ionizers safe for cats?

There is a questionmark over whether ionizers are safe for cats. Ionic air purifiers produce…

2 hours ago

Equity release to pay for a catio extension

Equity release is more popular nowadays because a lot of older people have most of…

8 hours ago

Ethical banks in the UK in 2020 and why cat lovers should use them!

How often do we think of alternatives to the high street banks? I don't or…

11 hours ago

“Care will kill a cat” – Ben Jonson

Ben Jonson is in the news today! On this day, 22nd September, in 1598, the…

12 hours ago

A reminder that cats reduce the risk of cardiovascular disease

Living with a cat companion when younger can protect against heart disease when older. I'm…

14 hours ago

YouTube film-makers are staging kitten rescues for money

YouTube film-makers are staging kitten rescues for money and pretending that the rescue is genuine.…

24 hours ago