BILL THE CAT: One in a Million (or one in 3,000, to be exact)!
June 24, 2020
By: Gina Lattuca, SPCA Serving Erie County Chief Communications Officer
UPDATE, JUNE 24, 6:30 p.m.: Bill has been adopted! When his story made national news today, we received more than 100 phone calls from potential adopters from all over the country! Fortunately, our boy will be staying home! Now named Milo, he’ll be living in Buffalo with Jomaira & Kiara!
BILL THE CAT is one in a million…or to be more specific, one in 3,000! Why? Because he’s a tortoiseshell kitty, and he’s a boy!
If you’re new to the cat world, that might not seem too exceptional. But those who have spent a little time in feline circles are paying close attention right now, especially after seeing Bill’s photo with that blue collar around his neck and realizing that this is a male tortoiseshell cat, an incredible rarity.
Genetics are pretty interesting when it comes to calico cats, and the same goes for tortoiseshell cats…even the “pastel” or dilute ones like Bill, with softer colors. Several genetic mutations cause these cats to develop coats with patterns that seem marbleized, much like the shell of a tortoise. And with the most common chromosome combos, all calicos and tortoiseshell felines are female. Well….almost all.
Think back to high school. Females have XX chromosomes, males have XY.
X carries the gene for coat colors; Y determines gender.
According to this article issued by Falls Village Veterinary Hospital in Raleigh, NC, “Orange coloring in cats comes from a gene in X chromosomes. Biology refresher: females have XX chromosomes. Males have XY chromosomes. So, it stands to reason that either a male or female cat can be or have orange coloring. The girls, though, are commonly calico, tortie, or orange tabby whereas the vast majority of males are only orange tabby. This is because only a cat with XX chromosomes can be calico or tortie.”
So if two X chromosomes are necessary in a calico or tortie kitten, and males are XY with just one X, how are male calico or tortie cats possible?
Very rarely, an extra strand of DNA 
(three chromosomes) is apparent in a male, making the male XXY. What does this mean? While the Y determines he is a male, the two Xs can, in fact, give him a calico or a tortoiseshell coat!
This is an incredibly rare occurrence. In fact, several sources researched cite a study by the University of Minnesota College of Veterinary Medicine that found only about 1 in 3,000 of these calico/tortoiseshell cats are male!
Undoubtedly, it must have occurred to someone throughout history to try and breed these cats, however, cats with three chromosomes are usually also sterile. Neutering is still important to help prevent negative medical or behavioral developments.
Because we don’t see many male calico or tortoiseshell cats at the SPCA Serving Erie County, Bill the cat is feeling pretty special these days, but he’s trying not to let it get to his head. Bill is waiting to meet his new family at our 300 Harlem Rd., West Seneca shelter! We have a feeling Bill will be scooped up quickly, but plenty of animals are at the SPCA waiting to become a part of your family! See our available animals here.
Adoption appointments can be made by calling 716-875-7360, ext. 207.
Thanks to the SPCA’s Lindsey Wood for Bill’s photos and videos!