Theory for the reason why grey cats are ‘blue’ (infographic)

Blue Female Scottish Fold12
Blue Female Scottish Fold12. Photo and breeding: Вероника Рыбалкина from Mariupol
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You know that in the cat fancy grey cats are called blue cats. The best known is the ‘Blue British Shorthair’. This is a grey-furred cat. Grey fur is caused by the presence of the dilution gene. It causes the melanin pigment clumps in each hair strand to be dispersed with gaps as shown in the infographic. Incidentally, I have relied on a drawing by Sarah Hartwell for the image of a dilute hair shaft. Thanks Sarah. She is the world expert of cat genetics in my view.

Theory for the reason why grey cats are 'blue'
Theory for the reason why grey cats are ‘blue’. Infographic by MIkeB at PoC.

The infographic explains my theory as to why grey makes blue in the cat fancy! It is a bit confusing to some. But then the grey fur of domestic cats does have a bluish tinge so the description by cat breeders is accurate. It is just that we are not looking at bright blue or navy blue!

The coat colour is a dilute black which is gray with a hint of blue. Comments are welcome to support of disprove the theory. As long as they are not too rude. The theory is based on the known physics as to why the sky is blue. The particles in the sky scatter blue light more than the other colours which make up white light.

I have used that theory to explain blue cats. The hair shaft when devoid of pigment is semi-opaque which is why all-white cats have hair shafts without pigment. White cats DO NOT have hair shafts that contain white pigmentation. The hair is has a milky appearance.

The same theory if blue light scattering is behind blue kitten eyes as they have no melanin pigmentation in their irises.

Here is a microscopic photo of a hairs haft showing the melanin pigment granules.

Melanin granules in a hair shaft
Melanin granules in a hair shaft. Image published under creative commons license.

The weakness in my theory is that white cats should have a slight blue tinge. Do they? If not, it may be because the keratin of the hair shaft has a slight yellow colour which counters the blue light. If that was the case the same would be happening in blue cats.

Below are some more pages on the dilution gene.

Siamese cats should have vivid blue eyes as per the cat associations' breed standards

How Siamese cats change their colours

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Dilution of cat coats (infographic)

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Dilute tortoiseshell

What is the blue-cream cat coat?

The blue-cream cat coat is a dilute version of the black-red cat coat which describes the tortoiseshell coat so the ...
Dilute tortoiseshell Maine Coon photo by Robert Sijka

Why are tortoiseshell cats nearly always female?

As you might well imagine, the reason why tortoiseshell cats are nearly always female is to do with the genetics ...
Dilution in cats - chart by Sarah Hartwell

‘Blue’ is the dilution of a black cat coat

Dilution refers to making a colour lighter as if mixing it with white. When black is made lighter is becomes ...
Russian Blue

Russian Blue is a black Russian moggy from the north of the country

In truth, the glamorous, pedigree, purebred Russian Blue is a black moggy from Russia. I am referring to the original ...
Tawny a dilute torbie cat

What is a dilute coat color in cats?

The term 'dilute' refers to the weakening of the colours of a cat's coat as if watered down. The colours ...

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