Two-Faced Cats: How Do They Get That Way?
At 15 years old, Frank and Louie was famous for its genetic mutation.
Named for the Roman god Janus, who was usually portrayed as having two faces, domestic cats with two faces are extremely rare, noted Leslie Lyons of the University of Missouri's Department of Veterinary Medicine and Surgery, who specializes in feline genetics. (Related: "R.I.P. Duecy: The Kitten With Two Faces.")
The animals also generally don't live very long due to health problems related to their deformity—making Frank and Louie's 15-year run that much more impressive, Lyons said.
The cause of Janus cats isn't completely understood, but "we know there's a variety of genetic mechanisms that could cause it," Lyons said. Only DNA testing can pinpoint the exact cause.
For instance, Janus cats may have too much of the sonic hedgehog (SHH) protein,