Calico Cats

Nov 1, 2011 · Updated Dec 5, 2013 · ·
  1. Anne
    Some people believe that calico cats are a breed, or that calico refers to a color of a cat. Since all cats are colored, calico refers to the pattern of how the coloring appears on the cat's coat.

    According to a leading expert in Feline Genetics, Dr. Elizabeth A. Oltenacu of the Department of Animal Science at Cornell University:

    "Early in its inception, a calico/tortie kitty is formed by a gene known as the white spotting factor. The white spotting factor effectively slows down the migration of cells across the kitten's body. One X-chromosome in every cell is switched off.

    This is a random happenstance, and when a tortoiseshell kitten appears in the litter, you will see a mix of two colors of hair on the kitten.

    In a calico kitten, the white spotting factor being present allows patches of cells with the same X chromosome shut-off to develop.

    The results are patches of white, orange, and non-orange in the kitten. The more white in a calico, the larger the patches of white, orange and non-orange because the migration of cells in the embryo is slowed. Once the color is in patches, you can see the effect of the tabby genes in the orange patches."

    Calico cats are overwhelmingly female. According to The Cat Fancier's Association Complete Cat Book; Persian calico cats have been accepted by CFA for years and calico Persians are always female and give birth to black-and-white or red and white bi-colored sons.

    Genetically, two X chromosomes are needed to produce a calico coat, which is why the majority of calico cats are females. If the colors are black/orange upon the coat, then the cat is a calico cat. If the colors are blue/cream instead of the standard black/orange, then the cat is a muted calico.

    Dr. Oltenacu further explains: "There's a gene on the X-chromosome that controls orange/non-orange color. One form (allele) determines orange, the other allele non-orange (usually black, but the actual color is determined by other genes on the autosomes). Neither form is dominant to the other, so a cat with one of each is a tortie.

    It has to be female, as this requires 2 X-chromosomes. Sometimes an abnormal male is born XXY instead of the usual XY, so can be tortie.

    Clearly, this male is the result of inaccurate separation of the chromosomes during egg or sperm formation. Usually, males are orange or non-orange, but not tortie as they have just one X-chromosome.

    Now, if the cat also has the white-spotting gene (again autosomal, not on the sex chromosome). This will cause the color to be in patches, rather than the diffuse mix of orange and black in the tortie. Hence the calico."

    If the majority of calico cats are female, then does this make male calicos valuable? For cat lovers, a calico cat, regardless of gender is valuable to the owner. Calico cats are quirky, independent, a tad stubborn and fun to be around.

    It is clear that calico cats have captivated hearts of cat fanciers around the world. On October 1, 2001 the state of Maryland was so enamored with this delightful cat that they declared the calico cat as their official state cat.

    Written by Mary Anne Miller
    The author wishes to acknowledge her great appreciation for Dr. Oltenacu's assistance in preparing this article.

    Comments? Leave them using the form below. Questions? Please use the cat forums for those!

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  1. puffball1355
    i had a tortoiseshell cat a while ago her name was Stormyfur do to the fact that she was mostly black with some orange splotches and stuff everywhere looking like a storm and her brother is an orange longhair with sort of a tabby pattern its very light though my pic is my current cat who is named Professor peaches
  2. jiskefet
    All my cats have a definite cattitude, but my torties and calicos all have/had tortitude. Not as much more aggressive than other cats, but they are and were all true divas. But that might well be because everyone seems to love a tortie or calico, so they are used to being spoiled and admired. Or maybe it is just because the diva attitude is more of a female thing, and torties and calicos are (except for the very rare XXY male) all female...
  3. peaches123
     my other cat Zoe,  a true tortoise with a lovely multi colored.coat. 
  4. tuxedoontheloos
    I had a tortie and a calico growing up, both from the same litter. The calico was shy but sweet. The tortie was a super dominate alpha cat, and a bit aggressive with strangers, but an absolute cuddle hog with us.
  5. plucy
    I just love my Calico cat. She's quirky, independant yet very sociable. Very , very curious too.
  6. wendy56
    I was reading on the calicos and found it interesting that only 1 in 5000 calicos are male, as the info above mentions that males are rare..
    I have a female calico and she had a brother who was orange, including the pads of his feet..he also had long hair and looked very much like a maine coon and a wonderful personality too..
  7. di and bob
    I think people got the idea of 'tortietude' because naturally all calicos are females, and it's the FEMALE that has attitude at times. I've had several female cats that definitely had an attitude, but only one male, (he was Siamese, so that probably explains it!)
  8. catspaw66
    I am wondering if the "tortitude" myth comes from the fact that calicos, being brightly colored, are observed more closely than non-calico. I say my ladies have tortitude, but actually it is just typical cat attitude.
  9. wendy56
    we have 2 female calicos and both sisters....their patterns are different, but are the calico pattern..
  10. Anne
  11. drbobcat
    I wonder where the "tortietude" nonsense began.  Many people seem to believe that torties are aggressive and difficult to manage.  I was surprised to hear even Jackson Galaxy, who ought to know better, claim that torties had attitude problems.  In shelter, I understand that Calicos are the second to last cats adopted, after black cats.  That's pretty strange considering how beautiful calicos are.  I accept the fact that breeds may exhibit different behaviors, some more chummy with people, some calmer than others for example, but I've never seen any evidence of attitude problems in torties. 
  12. lesliecat
    Hi Mary Anne. Good article. It seems that many people don't know the difference between a tortie and a calico.