Also known as Hemingway cats, boxing cats, cardi or mitten cats, polydactyl cats suffer from a congenital abnormality which results in additional toes. It is caused by a mutant autosomal dominant gene (meaning you only need one parent to pass the condition on) Pd.. Therefore, if a cat has extra toes, it is very likely that some of his or her offspring will also have extra toes due to the dominant Pd gene.
The word polydactyl comes from the Greek word "polys" meaning "more than one" and dactyl, which comes from the word "daktylos" or finger. Polydactyl cats are not a breed of cat. Polydactyly is found in many species of animal including humans, dogs, cattle, sheep, horses.
Eighteen toes is the normal number for cats. Five on each front paw, four on each rear paw. Polydactyly is relatively common in many domestic cats, and indeed some large species of cats. Two breeds of cat sometimes affected are the Maine Coon & the Pixiebob. Most cat bodies will not permit Maine Coons with polydactyly to be shown as purebreds and must show as domestic/part pedigree. Breeders have worked hard to breed out polydactyly in Maine Coons and kittens with the condition are on the decline as a result. Polydactyly is accepted in the Pixiebob however and they can be shown. As you can see from the image below, the extra paws make the paw look considerably larger than that of a "normal toed cat".
The history is not entirely known, the condition was first noted in 1868. Polydactyly is common among cats along the northeastern part of the US, especially the Boston area. Polydactyl cats are also known to inhabit South West England, causing speculation that the cats came over to the US on ships and formed a colony there &/or that polydactyl cats brought over from the UK mated with polydactyl cats in the US. Polydactyl cats were considered lucky by sailors.
It is a generally harmless condition although in some cases the claws can grow and shed abnormally. Also, the position of the additional toes can make your cat more prone to catching the claws on furniture etc. If the claws become torn, an infection can take hold. The front feet are more often affected, but it can involve all four feet. If extra toes are on the rear paws, the forepaws will also be affected.
In July 2010 I was contacted by Rory who had written an article on Bandit, a cat with 29 toes.
Ernest Hemingway was a lover of polydactyl cats, and his former home in Key West, Florida has become a museum which houses 40 plus cats, many of who are descendants of a white cat named Snowball owned by Ernest. Approximately half of these cats are polydactyls. You can read more about the cats at the Ernest Hemingway Home and Museum here.
Do polydactyl cats require special care?
Not really, just make sure that you trim the claws regularly (check them once a week) to prevent any problems developing such as ingrown claws or infection.
Do you have a polydactyl cat? We would love to add some more photos of polydactyl cats to this article. If you can help, please email us.
Special thanks to Rahr's owner for submitting her photo.
Yawning polydactyl courtesy of Andreanna Moya Photography
 Robinson's Genetics for Cat Breeders and Veterinarians.