Sandwalk on Calico Cats

Male cats can be black and white or orange and white, and so can female cats; but with the normal number of chromosomes, only female cats are black and orange and white, or “calico.” The reason is that the colour gene for black or orange is on the X chromosome. Males have only one to express. Females are expressing sometimes the X chromosome from their mother and sometimes the X from their father, and thus expressing different colours. The white is caused by another gene that suppresses colour, and can be expressed on more or less of the cat’s hide.

Dilute calico (Peek-A-Boo)

There’s been a discussion on Talk.Origins about calico cats—do they have to be female? The color pattern is an interesting combination of sex-linked genetics and epigenetics. Epigenetics is the inheritance of characteristics other than nuleotide sequence. In this case, it’s inheritance of an inactivated X-chromosome

Go to Larry Moran’s Sandwalk: Calico Cats for a detailed explanation.

The tortoiseshell cat has more blended colours than the calico, but the same sex-linked rules apply. This image from is called “Oswald and his sisters.” You can tell which kitten is Oswald because three of the kittens mix orange and black, while one has only black fur—so he’s the male.

four kittens, three tortoise-shell colour and one black

I had a long-haired, tortoiseshell cat given to me when she was thirteen years old. She lived for ten more years, making her the oldest cat in my veterinarian’s practice.

10 Responses to “Sandwalk on Calico Cats”

  1. kim Says:

    The oictures that are shown are soooovery cute and when i look at them, it makes me wan2 have and to hold. I am a total cat lover so i decided to research it and your article helped me alot!!! =] thanks!

  2. Amy Says:

    these cats are cute but not cut enough for me


    but i just wanted to just cuddl them and because my friend is a big , big cat lover she wants her own cat and i am willing to but it for her …..

  3. carmen Says:

    my cat just had kittens early in the morning yesterday and turns out she had a male calico cat! those are rare

  4. monado Says:

    How nice for you! If possible, when it’s a little older, contact a university genetics department near you and see if they want a blood sample or a hair follicle. Male calico cats sometimes have three sets of chromosomes (XXY) and they are often sterile. And cat genetics is not completely worked out.

  5. donna Says:

    My gray colored cat had a litter a four march 11 one calico, im assuming female. my question is how can i tell if they are male or female. they all look the same to me?

  6. monado Says:

    You can tell if you look at a kitten it’s are walking away from you with its tail up.

    Check the dark markings under the tail:

    * If they look like a colon (:), it’s a female.

    * If they look like a lower-case i, it’s a male. The longer mark is where the scrotum develops.

  7. Jay Says:

    XXY in humans is referred to as “Klinfelter’s Syndrome”

  8. JasonckRider Says:

    Hello. And Bye.

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