Explaining Venus Two-faced Cat Genetics

This page explains the genetics behind the fur pattern on the face of Venus, the famous “two-faced” calico cat. There is no doubt that Venus is a calico cat by which I mean a tortoiseshell-and-white cat. She has some white fur on her chest.

By “explain” I mean to the best of my ability and within the limits of the current knowledge of cat genetics. When you read Robinson’s  Genetics for Cat Breeders & Veterinarians you realize that there is still quite a bit to know.

Below is a collage that provides some initial information and below that I write further about the genetics behind Venus, the two-faced cat.

Venus Two-faced Cat Genetics
Venus Two-faced Cat Genetics. The photo of Venus is Photograph courtesy TODAY Show/NBC – an extracted image. Pictures of the calico cat (Maya) below Venus and the Black and white cat (Vic) are by fofurasfelinas (Giane Portal) and published with her permission.
Until September 7th I will give 10 cents to an animal charity for every comment. It is a way to help animal welfare without much effort at no cost. Comments help this website too, which is about animal welfare.

What I would argue is that Venus is actually a regular calico cat. “Calico”, incidentally, is an American term for the tortoiseshell and white cat.

The genes that produce the orange, black and white fur of the calico cat’s coat are listed in the collage above.

The gene that has produced the stark line that demarcates the boundary between the black fur (eumelanin) and the orange fur (phaeomelanin) is the white spotting or piebald gene.

The piebald gene is the one that creates the particolor faces of Ragdolls. These are pointed cats with a sharp white pattern on the points. Also the Snowshoe cat shows this sharp line produced by the white spotting gene (see picture).

Snowshoe cat picture copyright Helmi Flick
Snowshoe cat picture copyright Helmi Flick

In the case of Venus, the white spotting has caused an initial lack of color on the right side of Venus’s face (as we look at her) by stopping the migration of pigment producing cells to that side of her face. That would have left that side white. However, the presence of the orange fur gene (the O gene) has lead to the creation of cells that produce pigment for orange fur which have “stepped into the shoes” of the cells that do not produce pigment.

The presence of the white spotting gene has affected the color of Venus’s iris. The eye on the right as we look at her is blue. This is an iris without pigmentation. The white spotting gene is known to cause odd-eye color and a blue eye.

Gizzy - calico living with Elisa
Gizzy – calico living with Elisa

The fact that the line is exactly down the middle of the face is a one in a million chance, which makes Venus special. The pictures of the calico cat and black and white cat in the collage above show that the sharp demarcation on the face is commonplace. It is just a question of where the line (blaze) is and between which colors.

It is very hard to control the effect of the white spotting gene in breeding Snowshoe and Ragdoll cats. Venus is not a purebred cat. Ragdolls and Snowshoes are purebred and breeders use selective breeding to create the well positioned sharp lines between white and black.

For Venus, a random bred cat, nature took its course and by pure chance created a beautiful and arresting cat for humans. Cats themselves of course have no aesthetic preferences in respect of coat color and pattern.


  1. Associated pages: Calico cats – Tortoiseshell cats  – Tortoiseshell cat blaze.
  2. My thanks to Giane Portal – see her photos on Flickr
  3. My thanks to Today Show/NBC. This is a link to their website. If they want me to remove the picture just leave a comment and I’ll respond quickly and constructively.

13 thoughts on “Explaining Venus Two-faced Cat Genetics”

  1. Here is another cat in Raub, Pahang, Malaysia. This photo is on Flickr. It has received 38 views – very few yet the face is very similar to Venus’s. Photographer is by Nuraishah Bazilah binti Affandi.

    Two-faced cat

    • I have a new kitten who has markings exactly like Venus does. My kitten was born on May 09, 2013. I call her 50/50. Her eyes are both turning green now.

      Venus you are so cool!

      • Your cat is cool too. This sort of marking is rare. The blaze is not that rare but down the middle like Venus is pure chance in my opinion are very rare. Thanks for visiting and sharing.

  2. Thank you, Michael for explaining Venus cat genetics. We saw too many posts where they call this cat as a real ”chimera”, but clearly Venus is not one. Venus could be an example, showing that random bred cats can be surprisingly beautiful and unique.

    • Thanks for reminding us that random bred cats are often as beautiful as purebred cats. Here is a raggedy rescue cat with blaze down the center. OK the effect is no where near as brilliant but you can see that it happens all the time.

      Picture by LollypopFarm

  3. She is stunning, especially that her eyes are different. She really is ‘two-faced’ in the nicest of ways. Just out of interest, on the continent, in Europe, I have noticed that the common term for a Calico cat is -Tricolore -Tricouleur -Tricolora …deriving of course from latin and meaning 3 coloured. Oddly however, the German and Swiss Germans also use the same term which sounds much more French?Spanish?Italian (as opposed to something along the lines of ‘drei+farbe’ for 3+colour) . Furthermore, they use the exact same term in Slovenian/Croatian/Serbian so I can only assume most other Slavic languages too. Probably there is a direct translation for Calico in these languages but it’s never used in speech that I have noticed. In all these countries they also call Tabbys as Tigre/Tiger/Tigerli etc. Again totally un-technical, just the common names people use to refer to Calicos and Tabbys.

    Venus is lovely. She has a lovely name which I believe really suits her. No idea why, just gut feeling. I totally understand that the lady made arrangements to get this cat from quite far away, via airplane.

    • The Japanese Bobtail is a calico sometimes and the calico Japanese Bobtail is called the mi-ke, meaning “three-fur” (meaning three colors of fur: white, black and orange).

      The tortie and white cat is very popular and quite a special cat. It is almost always a random bred cat. It is a way for the random bred cat to outshine the more glamorous purebred cat. And of course they are almost always female due to the sex linked genetics.

  4. Venus is beautiful, but then to me, all cats are beautiful.
    One of the things I love about cats is the fact that they have no interest in what colour they are or how they look, their ‘what you see is what you get’ attitude is wonderful.
    Just think how much nicer this world would be if humans weren’t so obsessed with their looks.

    • Gosh yes, a thousand times yes. If we didn’t have this obsession with a person’s or a cat’s appearance things would be a lot better. We need to be more like a cat. I have always said we can learn from the cat. Unfortunately, in general, people are too arrogant and they don’t even know it.


Leave a Comment

follow it link and logo