Why Are Tortoiseshell and Calicos Mostly Female?
That’s my kitty Biggie Smalls, a dilute tortoiseshell. Big Poppa was the inspiration for the name, but my cat is female. Did you know that almost all tortoiseshell and calico cats are females? In fact, if you happen to know a male tortie or calico he’ll probably be the only one you’ll ever meet, since he’s a genetic rarity (and sadly, he’s also sterile). The reason that all calicos/torties are female comes down to genetics.
The gene for either the black or orange coloring is located on the X chromosome. Since females have two X chromosomes, they can have a black gene on one and an orange on the other and end up with both colors. Males have XY chromosomes so they can only have either orange or black coloring.
How Stuff Works has a cool video explanation here.
Image: Sarah Han
yay! Biggie makes her Pawesome debut!
Biggie is super cute- I have a male tortoise shell who looks a LOT like Biggie here. I didn’t know he was sterile though….
My gosh this picture looks exactly like my “Monkey” at home. Same colors, Same eyes, the only difference is he colors split down her face, down her nose also.