It’s funny how things like this come to light not because they exist at all, but because they broke a record. In this case the news isn’t that two-faced cats exist, or that they’re common enough to have a group name (Janus cats) because apparently everyone knows that already; no, the news is that one (or two) named Frankie and Louie is now in the Guinness Book of World Records for being the oldest one, like anyone actually cares about that.
So back to the real shocker: the Harvey Dent of cats. The medical term for it is disprosopus, which literally means “two-faced” in Greek. It’s caused by the embryo having too much of a protein called the Sonic Hedgehog Homolog — seriously. It’s called that because the hedgehog gene was discovered first, but then three homologous genes (ones that serve similar functions) were also found; the first two were named after kinds of actual hedgehogs (desert and Indian), but the third was named after the fictitious video game character. Anyway, the Sonic Hedgehog Homolog (SHH) controls a bunch of things during embryonic development, including how wide the face is — too wide, and things start to duplicate. So you end up with a cat like FrankenLouie that has three eyes, two mouths and two noses. (Interestingly, the Sonic Hedgehog Homolog is also involved in turning chickens into dinosaurs).
Normally, animals and people (yes, it happens to people) with this disorder don’t survive for more than a few days or weeks because of related complications. For example, a two-faced pig named Ditto died of pneumonia because he was breathing through one mouth while eating through the other and got food in his lungs. The reason FrankenLouie has been able to live so long is because it only has one functional esophagus.
About three years ago, a girl named Lali Singh was born in India with two complete faces: four eyes, two noses, two mouths. She was revered as a reincarnation of the warrior goddess Durga, who had three eyes. Raised without proper medical care, she died at two months old from a heart attack. She was the oldest known disprosopic human.
Here’s a video of Frankie and Louie:
From New York Daily News and The Sun