THE VICISSITTUDES OF TORTITUDE

"Tortitude," as believed by many pet owners and animal care workers, is a personality frequently found in tortoiseshell and calico cats, characterized by hostility and aloofness towards most persons coupled with an intense loyalty to one particular human being. Cats with this attitude are often characterized as "difficult." According to a 2014 survey by veterinarians at the University of California at Davis of over 1,200 cats, these types of felines are in fact more prone to anti-social behavior such as hissing, biting, swatting, and scratching when a human (other than the one that the particular cat worships) attempts to interact with them.

A tortoiseshell cat essentially is a feline with two different colors (other than white) of fur, while a calico has two different colors plus an area of white. The fur color results from pigment expressed by an X chromosome, so a cat with two different non-white fur colors has to have two X chromosomes, with each chromosome specifying its own pigment for a particular section of the cat . This explains why 2,999 out of 3,000 tortoiseshell and calico cats are female, as only females have two X chromosomes--except for the very rare male who has the feline equivalent of Klinefelter's syndrome with two X chromosomes and a Y chromosome.

Male tabby cats with dark stripes over a lighter background hue do not violate the above rule, as both the dark stripes and the lighter background are a result of the same pigment being applied in different concentrations and are expressed by its single X chromosome. An orange and white male, or an orange, black, and white female calico also is "legal," as the white fur does not count as a color, since it is a result of no pigment being expressed at all on the white area of the animal.

I tend to believe in "tortidude," as we once had a gray calico named Miranda with little smudges of peach color and a white chin and chest. She was absolutely disdainful of most humans and would intercept any attempts of affection with scratching and biting. With me, however, and much to the disgust of my wife, Miranda was absolutely devoted and would crawl onto my stomach for long sessions of petting and purring to the point of drooling.

Could it be that "tortitude" is not a function of the pigment-portions of the X chromosomes but is instead merely a reflection of the fact that the animal is a female? You must be crazy if you think that I would even approach acknowledging that possibility with a ten-foot (3.048 meter) pole.

MIRANDA