Frank and Louie, a ragdoll cat born with two faces, wasn't expected to live more than a few days, but for years he defied the odds. The cat passed away last week at the age of 15.

Janus cats, named after the two-faced Roman god, are extremely rare and typically don't live long due to health problems related to their deformity.

However, Frank and Louie holds the world record for longest-living Janus cat.

A breeder brought the day-old kitten to the Cummings School of Veterinary Medicine at Tufts University in 1999 to be euthanized, but Martha "Marty" Stevens, an employee of the school, offered to adopt the kitten.

Stevens tube-fed the tiny cat for three months, and eventually Frank and Louie learned to eat and drink on his own.

The unusual-looking feline had two functioning eyes, one blind center eye, two noses, two mouths and one brain.

Experts say Frank and Louie's abnormally long life was likely due to the fact that his other organs weren't doubled.

However, in November, the cat's health began to decline and veterinarians suspected he had cancer. When Stevens was told Frank and Louie was likely suffering, she chose to have him euthanized.

Frank and Louie's condition was caused by a rare congenital disorder known as diprosopus.

chick with two facesUnlike the phenomenon that causes conjoined twins — the incomplete separation of two embryos — Frank and Louie's two faces results from the abnormal activity of a protein that causes the duplication of body parts.

The condition isn't limited to felines. It can occur in any vertebrate, including humans, and there have been documented cases of two-faced chickens and pigs, among other animals.

Most human infants with diprosopus are stillborn, and instances of humans with the condition living for more than a few hours are rare.

Below, watch a video of Stevens with Frank and Louie that was made in 2011 after the feline earned a place in the Guinness World Records for his long life.

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Photo: (chick with diprosopus) Wikimedia Commons