Q I have a male tortoiseshell cat approximately 12 weeks old. Can you tell me how much he is worth?

A The Cornell Feline Health Center receives calls from people with tricolored (tortoiseshell and calico) male cats fairly regularly. Realizing that such cats are uncommon, folks call in hopes that their cat will pave the way to fame and fortune. Well, don't give up your day job just yet: These fellows have no greater monetary value than any other cat.

About One in 3,000
They are rare, though. Estimates vary, but one report gives odds of about one in 3,000. For clarification, tortoiseshell cats (torties) have a black coat with patches of yellow or orange. A calico cat is a tortie with patches of white. Torties and calicos can have a dilute coat pattern in which the black is replaced by gray and the orange is replaced by a cream color. For simplicity, all these cats are classified as tricolors.

It's All in the Genes
For a genetically normal cat to have both red and black coat colors, it must have two X sex chromosomes: one to carry an orange gene, and one to carry a non-orange gene. Normal females carry two X sex chromosomes (XX) - and can have both orange and black. Genetically normal males are XY - and can't be both orange and black. So for a male cat to be tricolored, something must be genetically amiss. One of the more common genetic abnormalities, called Klinefelter's syndrome, results in sterility.

But don't think you can skip having this little fellow neutered; some tricolored males are fertile, and I've personally seen some kittens sired by a calico Tom.