Tri-Color Cat Defies Genetic Odds

Tri-color cats are almost always female because two X chromosomes are required to produce the orange, black and white color pattern.

The odds of a male cat being born with these colors is very rare. Photo courtesy: Kara Kuh

(SALEM, Ore.) - Willamette Humane Society (WHS) staff say they were surprised to discover that a five-month-old tri-color kitten surrendered to the shelter recently is a male. The odds are only about 1 in 3,000 that a cat with the three distinct colors – orange, white and black – will be a male.

In her 21 years practicing veterinary medicine, Dr. Jacque Harter, shelter veterinarian and medical director for Willamette Humane’s new low-cost spay and neuter clinic, says she’s never seen a male tri-color, or in this case, a “torbie” - a color pattern that is a combination of a tortoiseshell (black, yellow and cream markings) and a tabby (gray or tawny coat mottled with black).

Tri-color cats are almost always female because two X chromosomes are required to produce the orange, black and white color pattern. Male cats have only one X and one Y chromosome. In extremely rare instances, however, a male kitten is born with tri-color markings due to an extra X chromosome.

Male tri-color cats are usually born sterile, but WHS staff stress the importance of neutering him to reduce undesirable behaviors - including the desire to roam, aggression, and spraying.

Dr. Harter performed the neuter surgery on the cat (named Monte) in Willamette Humane’s new low-cost spay and neuter clinic on Tuesday, January 19.

He will be available for adoption starting Thursday, January 21.

To view all pets available for adoption at Willamette Humane Society, go to willamettehumane.org or call (503) 585-5900. For information about spaying and neutering, call the WHS Spay & Neuter Clinic at (503) 480-7729.