Also known as Hemingway Cats (he wrote about them), Mitten Cats (their extra toes often look like a thumb) or Boston Mitten Cats (they are prevalent in Boston and the East coast), they can have up to seven toes on each foot.

Polydactyl Cats are known for being a hardy, sturdy cat with relaxed and mellow personality.  They tend to be large as an adult. Polydactyl Cats have extra toes because of a dominant gene. This means that kittens of a Polydactyl mother may have extra toes even if the father does not. Because the gene has incomplete expression, however, it is not certain how many toes the kittens will have.

Polydactyls come in lots of varieties in hair length and coloration.  Some have bobtails and shorter bodies than those with long tails and hind legs are noticeably longer than the front legs. Of course, they all have feet with their extra toes. Some Polydactyls have extra toes looks like a thumb. In others, a three-toed foot attached to the cat's four-toed foot. The extra toes may be found on the front feet only or on the back feet only, or all feet may have extra toes.