* Differences Between Tortoiseshell and Calico Cats
Tortoiseshell and Calico Color Patterns
Tortoiseshell and calico cats come in a great variety of the colors, including black, red, and white. Unlike what some people think, they're not different breeds. Their differences lie in their special color patterns. In this article I'll explain how the tortoiseshell pattern compares to calico. Both have the same colors (white, orange, and black) but the patterns are different. While a tortie coat might not include any white at all (like the cat on the above photo), calico coats always include white.
At home, we have one tortoiseshell cat (Chewy) and two calico cats, one with plain colored patches (Lilo) and one with tabby colored patches (Red). It was when I did my research for this article that I discovered that Red is a calico. She has quite a lot of of white in her coat and her colored spots are not plain, but brindled. She is what's called a tabby calico.
In The Netherlands, we use only one word for these cats: lapjeskat. In English this means "patched cat."
Curiosity is the very basis of education and if you tell me that curiosity killed the cat, I say only the cat died nobly.— Arnold Edinborough
Tortisshell and Calico Color Patternn
Why Tortoiseshell and Calico Patterns Are Different
Most tortoiseshell and calico cats are females. They have two X chromosomes, one for orange (XO), one for black (XB). They only pass one on to the next generation. Males, however, have one X chromosome and one Y chromosome, which is either orange (XO) or black (XB).
Here is more detail about how this works:
Female XO + Male XO = orange
Female XO + Male XB = mixed orange+black pattern
Female XB + Male XO = mixed orange+black pattern
Female XB + Male XB = black
Whenever a male tortoiseshell or calico cat is born, the father most likely had an extra X chromosome, XXO or XXB, which is a rarity.
Pigment Genes in Cats
Pigment genes are expressed in what we call melanocytes. When there is a mixed pattern, these genes surface to the skin and the colors mingle randomly, giving the cat that special brindled look. In tri-colored cats, there's a second gene interacting, which has no pigment at all. This results in either small or large white spots. This is why some cats look completely white but are not albino. Genetically, they have a brindle pattern, with a dominant white which won't let the orange and black surface to the skin.
- The only difference between a tortoiseshell and a calico is the absence or presence of white spots. The calico pattern has an extra spotting gene, which produces white, unpigmented spots. Those white spots can be either small or very big. The spotting gene overrules the color gene, so you can have an almost white cat with a few colored patches, or a colored cat with a few white spots. Most of the time the colored patches are in the same color range as tortoiseshell cats: orange (red), black, and white.
Tortoiseshell cats (torties) very often have only two colors, red and black, with no white at all, but color include black, orange (red), brown, black, cream, cinnamon, and blue. These cats often have a mottled or brindled coat. They can either be short haired or long haired and the color patterns can vary from very dark to very light.
Photos of Lilo the Calico CatClick thumbnail to view full-size
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My Calico Was a Stray Cat
One evening in 2002, I went into the barn and there she was: A cute, but skinny, teenage kitten with very big eyes. She was shy, but also hungry, and she ate until her belly was full. She may have come from a farm in the neighbourhood. They often have cats to keep the mice away. Or maybe she was just thrown out of some car. Who knows?
That's how Red came to live with us. It took a lot of begging and spoiling before she allowed me to pet her, but she never allowed me to pick her up and hold her in my arms.
Photos of "Red"Click thumbnail to view full-size
When Red came into the house, we quite soon discovered that she must have had a difficult life before she ended up in our barn. She must have had some very bad experience with human encounters.
She comes to sit on your lap, purrs a lot, and actually loves to be petted, but when you pet her too much or you stroke her right to the end of her body, she suddenly will grab you with her claws. Her ears go back to her neck and she turns into a wild animal. You'd better get her off your lap by then. You can't pick her up, so the best way to do it is to stand up and she'll jump off. She has always been like that, all nine years long, so we keep her away from visitors.
Cats with an Attitude
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© 2011 Titia Geertman
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