At only four-weeks-old, a tiny tortoiseshell kitten named Burrito is already something special. He was dropped off at the Animal Welfare Association in Voorhees, NJ after being found with his littermates as a stray. The tiny ball of fluff doesn’t look much different than his siblings, but the fact that’s he’s a male makes him 1 in 3,000.
Due to genetics, the odds of a tortoiseshell or calico cat being male are extremely low. Distinguished by their mottled brown, black, cream, and white-colored coats, nearly all tortoiseshell cats are female. The reason why lies within their genetics.
The genetic marker for tortoiseshell coloring is a recessive trait that is only associated with the X chromosome. In order for it to show up, a kitten needs to be XX, which in terms of genetics, means female. Males are distinguished by being XY. The fact that little Burrito is both male and a tortie means he’s a genetic anomaly—an XXY. According to Vet Street, cats like Burrito only make up .0003% of the world’s cat population.
Burrito’s secret was revealed by AWA veterinarian, Dr. Erin Henry. She said in an interview with CBS Local in Philadelphia, “When I turned little Burrito over I was so surprised. I’ve examined thousands of kittens while working at AWA and they are so rare that he may be the only male tortoiseshell I’ll ever see again. ”
While Burrito’s genetic makeup most likely means he will be unable to breed, his rescuers don’t think his medical history will keep him from being adopted. In fact, it might help. Burrito is still about a month away from being ready for adoption, but when the time comes, rescuers expect his rare condition and recent internet fame to attract a quick match. Despite his genetic rarity, little Burrito’s adoption fee will be the same as every other kitten at the shelter.