What percentage of calico cats are male?

Maine Coon Jennie - Calico
Maine Coon Jennie – Calico. Of course she is female. She is also beautiful.
Two useful tags. Click either to see the articles:- Toxic to cats | Dangers to cats

About 0.033% of calico cats are male, we are told. I am not sure how accurate this figure is. Represented a different way it is one male calico cat for every 3000 female calico cats.

In fact, as their existence is theoretically impossible there has to be a genetic anomaly for a male cat to be a calico cat. The male calico cat is described as “very rare”. They are nearly always sterile because they have XXY chromosomes. This causes a condition called Klinefelter’s syndrome (in people), which is the result of additional X genetic material in males. In people, this syndrome can cause the person to be taller than usual with less muscle control and weaker muscles. I wonder if it affects cats in the same way. Update: please see Sarah Hartwell’s comment. The main cause of tortie male cats is a thing called “chimerism”. This is when two fertilised eggs fuse to become a single kitten. I’ll ask Sarah Hartwell to explain it in an article! There is a link to her site in the comments.

As they are very rare they are possibly more valuable than a typical pedigree cat if they are a pedigree cat. However the sterility prevents breeding, devaluing the cat.

Calico” is an American term meaning tortoiseshell and white. In the UK cat fancy the word “calico” is not used as far as I am aware.


  1. Dilute calico cat
  2. Calico cat behavior (some people think they have a certain character)

17 thoughts on “What percentage of calico cats are male?”

  1. Sarah had already posted one of the links to the article on chimeras. The one I posted was sort of an overview.
    There is a wealth of information on her site about these subjects. Here are some more:

    Early Reports & Studies of Tortie Males http://www.messybeast.com/mosaicism5.htm
    Klinefelter Syndrome cats http://www.messybeast.com/mosaicism3.htm
    ” A Torbie Dynasty?” http://www.messybeast.com/mosaicism4.htm
    Gender Anomalies in cats http://www.messybeast.com/mosaicism2.htm

  2. Thanks Sarah for the comment here. I’m a longtime reader of your site and had learned from your articles on this. I would encourage anyone who wants to read more details to check out Sarah’s extensive treatment of the subject here http://www.messybeast.com/mosaicism.htm

    A lot of writings elsewhere need to be updated. We always used to hear / read that tortie male cats usually had extra X chromosome(s) and were nearly always sterile. but I kept hearing of fertile tortie males. So it makes sense that the usual cause is something different.


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