The Complexity of Cat Colours and Coats

They say blondes have more fun, and redheads have fiery tempers. But what about our furry felines? What does the chic ombre of Siamese points say about them? And the orange stripes of a ginger tabby? There is some interesting science behind cat colours, and we are tickled pink to share it with you.

To really understand cat colours, we have to look at the DNA that encodes them. This may sound like hard work, but it’s worth it!

The genes for cat colours are located on the X chromosome.

Females have two X chromosomes (XX), while males have only one (XY). A male kitten gets a Y chromosome from his father, and an X chromosome from his mother, so he can only get colour genes from his mother. That’s why male kittens tend to resemble their mothers – either they are the same colour; or one of the mother’s colours; or a dilute form of her colour. Female kittens get an X chromosome from each parent so they can be any combination of the parents’ colours.

The limitation of colour genes to just the X chromosome explains why certain colours are associated with specific genders.

For example, approximately 75% of ginger cats are male(6). This is because the ginger colour comes from a gene mutation of the X chromosome, and it is less likely to occur on both the X chromosomes of a female cat than the single X chromosome of a male(2).

Approximately 99,9% of calico and tortoiseshell cats are female(4). This is because an X chromosome can carry a black or an orange gene, but not both - so a cat that has both colours must have two X chromosomes. Male cats would either have the black or the orange gene so will be one or the other. Very rarely, a male cat will be calico because of an anomaly whereby it has two X chromosomes and one Y chromosome. XXY Syndrome, as its known, can result in health problems, and male calico cats are usually sterile.

Brown cats are very rare, because this colour is encoded by a recessive gene. The only exclusively brown cat breed is the Havana Brown, and it’s estimated that there are fewer than a thousand of them in the world.

White cats make up about 5% of all cats(7). Roughly a third of these cats have blue eyes, and of this subpopulation, 60-80% are deaf(7). Not all white cats with blue eyes are deaf because there are multiple genetic combinations which can result in these physical attributes, and only some are linked with an abnormality of the inner ear which leads to deafness. White cats with two different colour eyes are sometimes only deaf on the side of the blue eye.

There is a difference between a white cat (whereby the gene expressing white coat colour dominates over other genes) and an albino cat (where both parents pass down a recessive gene which results in lack of pigment)(7). The easiest way to tell the difference is by looking at the eyes. Albino cats have very pale, pinkish-blue eyes; while white cats have blue, green or amber eyes.

Point colouration refers to a coat that is pale on the core body area and darker on the extremities, such as in Siamese and Himalayan cats.

Point colouration is a result of genetics but is influenced by the environment. Genetically, it occurs because of a mutation whereby the enzyme that produces melanin becomes heat sensitive. This means that the enzyme does not do its job of pigmenting the coat in warm areas of the body; so these remain pale. It is effective at darkening the extremities, such as ears, paws and tail, because these areas are cooler.

Because the pigmentation process is influenced by temperature, pointed cats in cool climates may be darker than those in warm climates. A breeder would be able to manipulate coat darkness by controlling ambient temperature(3). Also, pointed cats tend to get darker as they age – possibly due to decreased circulation(3).

Scientifically speaking, there is no clear evidence which shows that cat colours are genetically linked with certain personality traits. However, according to surveys, cats are perceived differently according to the colour of their coat.

Orange tabbies are generally perceived as friendly; black cats as mysterious and demure; and white cats as aloof, lazy and calm(1). Calicos and tortoiseshells are commonly seen as feisty and unpredictable(5). Whether there is any truth to these opinions remains to be proven, but they do appear to affect adoption rates within shelters.

Does your cat fit into the personality profile of its colouring? Let us know in our private Facebook group! We’d love to hear from you!

References:

1. Anwar, Y. (2012). Don’t be so fast to judge a cat by its color, study warns. Berkeley News. Retrieved September 3, 2021, from: https://news.berkeley.edu/2012/10/23/cat-color/

2. Cats Protection. (2018). Why do cats come in so many different colours? Retrieved September 2, 2021, from: https://www.cats.org.uk/cats-blog/why-are-cats-different-colours

3. CatWatch. (2019). Climate-controlled color: why it happens. Retrieved September 4, 2021, from: https://www.catwatchnewsletter.com/features/climate-controlled-color-why-it-happens/

4. Donnelly, C. (2021) 9 beautiful calico cats and kittens. The Spruce Pets. Retrieved September 2, 2021, from: https://www.thesprucepets.com/calico-cats-photo-gallery-4031810

5. McCracken, S.L. (2020). Cat colors – get the fascinating facts behind cat coats and patterns. Catster. Retrieved September 3, 2021, from: https://www.catster.com/cats-101/different-cat-colors

6. Ridley, L. (2021). Is it true that most ginger cats are male? BBC Science Focus Magazine. Retrieved September 4, 2021, from: https://www.sciencefocus.com/nature/is-it-true-that-most-ginger-cats-are-male/

7. Staab, W. (2015). White cats. Hearing Health & Technology Matters. Retrieved September 4, 2021, from: https://hearinghealthmatters.org/waynesworld/2015/white-cats/