Calico cat

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In October 2001, the Calico cat became the official cat of Maryland, as it shares its colors with both the Baltimore oriole, which is the state bird, and the Baltimore Checkerspot butterfly, which is the state insect. Although the Calico has been adopted by the state of Maryland, it can be found around the world and has been known to occur in breeds as disparate as the Manx, Persian, Japanese Bobtail, and Domestic Short Hair.

The term Calico refers not to a particular breed of cat, but to a certain coloration pattern that is found across different breeds. In order to be considered a Calico, a cat must have three distinct colors that appear in patches. The three most common colors are white, orange, and black, although certain diluted color variations can also be designated as Calico. The first color must be derived from the red gene coloration; most people call this orange or ginger. There must also be a significant amount of white, and some variation in the third color (which is traditionally black) is sometimes found. Acceptable third colors include blue (bluish-gray), chocolate,

Calico cat fur

Image from www.freerangestock.com

lilac (light rose-beige), cinnamon, or fawn (a pale buff color). Calicos are distinguished from Tortoiseshell cats in the way their colors are presented. The more common Tortoiseshells have coats with colors that are swirled and mixed together, whereas Calico patches are in distinctly colored blocks.

The overwhelming majority of Calico cats are females, although it is thought that roughly one of every 3,000 are male. These males are almost always sterile, as they must have one extra chromosome for the distinctive Calico pattern to be expressed. This genetic abnormality occurs because the gene that governs how the red or orange coloring is displayed is only found on the X, or female, chromosome. Therefore, every Calico or Tortoiseshell cat must have two X chromosomes, making the vast majority of them female.

In the rare cases of male Calicos, there is a genetic anomaly causing them to have an extra chromosome, so instead of having just two XX chromosomes, they also have one Y (or XXY). So far, it is unclear whether these genetically abnormal male cats suffer from any ailments associated with this mutation, but it seems possible that they might. The one known problem for these male Calicos is that only 1 in 10,000 can reproduce.

Gould, Laura. Cats are Not Peas: A Calico History of Genetics. New York: Copernicus Press, 1996.