Q: I have heard that all orange tabby cats are male, and to find one that is female is rare and worth up to $1,000. I also have heard that calico cats and tortoiseshell cats are female and to find a male is just as rare and prized. Is there any truth to this?
A: Your first statement is incorrect. Most, but certainly not all, orange tabby cats are male. It’s about 80/20 male to female. We have many female orange tabbies in my practice. There is no monetary value, per se, associated with a female orange tabby cat. Calico and tortoiseshell cats, however, are almost always female.
Here’s how it works. To have black and orange in the same cat, you need two X chromosomes. Two X chromosomes mean the cat will be female. Male cats need a Y chromosome and are XY.
Occasionally a mutation will arise during embryonic development and a kitten will be born with an extra chromosome: XXY. The two Xs allow for it to be black and orange. The Y makes it a male. This is how you get a tortoiseshell or a calico male cat. They’re uncommon (one out of 3000 are male), but don’t get your hopes up about breeding them for money. As a result of this mutation, most of them are sterile.
Regards,
Arnold Plotnick, DVM