Thanks to a rare genetic condition, a kitten in China was born with a shocking feature—two faces.
Video from Chongquing, a region in southwest China, shows the newborn kitten's abnormal rare condition. It's small, tiny body is topped by two faces, each with separate, individually mewing mouths and wiggling noses. One face is dominated by white fur and the other by black, making the kitten look even more striking. But beneath, only one body supports the two faces.
The kitten reportedly died after only two days of life. It's a fate frequently met by cats with this rare condition. It's often called a "Janus cat," named after the mythological, two-faced Roman god Janus.
While the kitten in Chongquing gained online popularity during its short-lived life, it's far from the most famous Janus cat.
That title likely goes to a cat named Frank and Louie (sometimes Frankenlouie). The Janus cat lived to be 15 years old, dying in 2014, and holds the Guinness world record for the longest lifespan of its kind. (Read more about Frank and Louie's life.)
During a 2014 interview about that famous cat, Leslie Lyons, who specializes in feline genetics at the Univeristy of Missouri's Department of Veterinary Medicine and Surgery, explained that the cause of the genetic mutation that gives cats two faces isn't entirely understood but is likely explained by how kittens develop in the womb.
According to Lyons, scientists believe Janus cats contain irregularly high levels of a protein called sonic hedgehog (SHH). The protein dictates how typical facial features like eyes, noses, and mouths develop. In lab tests, chicken embryos injected with high levels of SHH have developed features like two beaks and eyes spaced far apart. (Learn more about what cats really think of us.)
Genetic mutations have also given cats incongruous features in one face. One cat named Venus rose to fame in 2012 when images of its face, one half black and another orange, showed how genetic variances during the cat's development resulted in the bizarre coloring.
Cats aren't the only animals that have been born with two faces. Any mammal is subject to the genetic mutation, but lifespans are typically bleak. Two faces can put stress on the shared internal organs, and animals in the wild can become easier targets to predators or have difficulty feeding.