The majority of torties — 99.6% — are female, making males incredibly rare. The reason for this comes down to chromosomes. Two X chromosomes are required to produce the signature tortoiseshell coat colors and patterns. Just like humans, female cats have two X chromosomes and males have an X and a Y chromosome.
It’s All About Chromosomes
Cats’ orange coloring is caused by an X chromosome gene. High school biology refresher: females have XX chromosomes. Males have XY chromosomes. Therefore, it makes sense that a male or female cat could be orange in color. However, the majority of males are exclusively orange tabby, while the girls are typically calico, tortie, or orange tabby. (This has caused the false belief that orange tabbies are exclusively found in male cats; in reality, most are just because females are more likely to have other orange variations.) This is so that a cat can only be tortie or calico if it has XX chromosomes.
So How is There Ever a Male Calico or Tortoiseshell Cat?
It’s a genetic anomaly! Three chromosomes are uncommon in cats and humans alike. A male cat with XXY thus has the two necessary Xs to potentially make him an extremely rare and gorgeous cat. After endocrinologist Harry Klinefelter, who initially recognized the condition in the 1940s, these XXY guys are referred to as Klinefelter males.
Now, don’t assume that you can breed for a rare coloring in male cats just because it is possible to get it. The vast majority of cats with three chromosomes are sterile. That’s part of why it’s so rare to begin with. Therefore, if you own one, treasure him for the unique, multicolored, autumn-kissed gem that he is!
Tortoiseshell cats are usually female.
It’s likely that any tortie you’ve ever met was a woman. Approximately 1 in 3,000 tortoiseshell cats are male, which makes them extremely rare. Nearly all tortoiseshell cats are female. This is due to the fact that male cats only have one X and one Y chromosome, whereas two X chromosomes are required to produce the distinctive tortoiseshell coloring of black, orange, and yellow/gold. Because they have an extra X chromosome, male torties are extremely uncommon XXYs. Male tortoiseshell cats are even rarer since they are typically sterile due to a genetic anomaly causing this!
FAQ
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