The term polydactyl means many digits. (Digits meaning fingers or toes.) A polydactyl animal has more than the normal numbers of fingers or toes. The term "poly" means many, and the term "dactyl" is a Greek word for digit - toe or finger. There are a number of other interesting meanings for the term dactyl as well.
In veterinary medicine, polydactyly is seen most commonly in cats, usually on the front feet. The cat's paws will have a big, "mitten-like" appearance. Normal cat (and dog) front paws have 4 main toes and one dewclaw (small toe up on the leg) and 4 toes on the back feet.
A polydactyl animal will have more than 5 front toes and more than 4 hind toes. The exception being some breeds of dogs that normally have "extra" hind dew claws as part of the breed standard, such as the Great Pyrenees. The breed-specific dew claw may be a single extra claw or a "double dew claw," two claws.
Should extra toes / claws be removed? This varies greatly with the individual animal. In polydactyl animals, the foot has a different anatomy than "normal" animals, so the wear and tear on the toes and claws will be different.
The most common problem for polydactyl cats is that the extra toe claws will grow into the pads, causing pain and infection. The claws on the extra toes need to be monitored and clipped regularly to prevent problems. If the claw is too difficult to access for trimming, the claw may need to be removed surgically.
Photo: "The cat with thumbs" © JP Puerta on Flickr
