Are Cats Supposed to Have an Extra Toe?

"Mitten cats," "thumb cats" and "Hemingway cats" are some of the names given to polydactyl cats, or cats born with extra toes. Normally, cats are supposed to have a total of 18 toes: five on the front paws, and four on the back. Polydactylism is a genetic variation that results in a cat having extra toes on his front paws and, in rare instances, on his back feet.

  1. The History

    • The name "polydactyl" comes from the Greek words "poly" meaning "many" and "dactyl" meaning "digits." Polydactyl cats have been around a long time. Legend has it that the first polydactyl cats were brought to Boston by English Puritans in the mid-1600s. Their offspring then traveled by trading ships to Yarmouth, Massachusetts and even Halifax, Nova Scotia, where a higher incidence of polydactyl cats can still be found today. Sailors believed these cats were lucky, and that their extra toes helped them balance on board the ship. They also believed the extra toes made the cats experts at catching mice. In Europe, however, polydactyl cats were associated with witchcraft and often destroyed.

    Do Some Breeds Have Extra Toes?

    • It is not clear that polydactylism affects any one breed of cat over another. According to Dr. Arnold Plotnik of Manhattan Veterinary Specialists, historically unregistered Maine coon cats had a 40 percent incidence of polydactylism in the breed. Some people believed that the large mitten-like feet helped them walk across the snow. Other legends reported that the large size of the Maine coon cat's polydactyl paw helped him catch fish from streams and rivers. Breed standards, however, required that polydactylism be bred out of the Maine coon breed.

    The Science Behind the Toes

    • The gene that causes polydactylism in cats can cause a cat to have either extra toes or extra rear dewclaws, which are non weight-bearing toes located higher up on the paw, on the animal's "wrist" rather than his foot. Cats naturally have dew claws on their front feet, but rear dew claws are considered to be an example of polydactylism. It is very rare for polydactylism to affect both the front and hind paws. The gene for polydactylism is dominant in cats, and can appear in both males and females. Nearly half the kittens from one parent with the polydactyl gene could inherit this trait.

    Hemingway's Cats

    • Polydactyl cats are often associated with famous writer Ernest Hemingway, who lived in Key West, Florida. Legend has it that a ship's captain gave Hemingway a six-toed polydactyl cat named Snowball, and that the overabundance of polydactyl cats in the local population can be traced back to this original cat. Today, the Hemingway House museum is home to at least 50 cats, half of which are reported to be polydactyl cats.

    Health Risks

    • There are no additional health risks or concerns with most polydactyl cats. However, the gene mutation can also cause missing or deformed bones in the foot and this can lead to a disability. The extra toe or toes on the foot will grow nails that need to be trimmed. Sometimes the nail bed on the extra toe will be slightly deformed, and this may cause the nail to grow inward. Make sure you monitor your polydactyl cat's nail growth and take him to the vet at the first sign of a problem. This will prevent the pain from an ingrown claw.