Polydactyl cats have one or more extra toes on one or more of their feet. Unlike other species, which are devastated by extra toes, most polydactyl cats function perfectly well.
A normal cat has 18 toes, five on the two front feet and four on the two back feet. Cats with an abnormal amount of toes were considered to be associated with witchcraft in Europe in the 19th century and were largely killed, so the trait is rare in Europe. However, it's popular in the United States because early settlers believed the extra digits were lucky. They were considered to be better hunters and came over with the settlers.
Polydactyl cats can have as few as one extra digit or up to four extra digits per foot. The record is a cat named Jake with 28 toes. It can manifest itself in many ways, such as an extra digit that looks like a human thumb, duplicate dew claws, extra toes that form a wide foot called a patty foot or extra undeveloped toes that are tucked between developed toes.
Polydactyly is more common on front feet and can't appear on the back feet unless it appears on the front feet. Sometimes, it isn't apparent on the back feet because the extra toes haven't fully developed and are hard to see.
Some extra toes have extra joints as well, which allows them to work much like human fingers. Owners of these cats claims they can move and hold items like a human and have an increased ability to escape by opening doors and latches.
Harmful Polydactyl Traits
Some forms of polydactyly cause twisting in the limbs, which affects their development and can cause a significant handicap in cats. Because kittens with either form of polydactyly look similar, X-rays are required to determine if the kitten will have additional deformities later in life.
Otherwise, the most common problem facing polydactyl cats are toes that grow in differently, causing imbedded nails that may cause pain and must be removed. Some of them can't align properly and tuck under the foot, making it difficult for the cat to walk.
Some toes are shorter than others so the claws grow out longer and make it difficult for cats to walk or scratch. Some toes that curl under have nails that grow toward the pad and need to be clipped frequently or removed.
Some toes are fused together with the nail beds fused together as well. These are more likely to twist abnormally. Any twisted or abnormal nail has increased chance of catching on furniture and carpeting, which could cause pain for your cat.
In general, polydactyly doesn't cause many additional problems. Cats can function perfectly well with extra toes and can even use extra joints as an advantage in hunting. More than anything else, it just causes some interesting combinations of toes on your cat's feet!