should i worry about my cat's extra toe?

Have you ever seen a cat with an extra toe - or two - or three?  This is a condition called polydactyly, from the Greek for "many toes," and the cat is polydactyl.

It happens because of a genetic variation that affects where toes form as the paw develops in the embryo. It is usually inherited as a dominant trait, but its expression can vary considerably — one kitten might have one small extra toe, while another might have two or three.

For most polydactyl cats, there's not much to worry about. But I've seen some cats where the extra toe is small or slightly out of position, so the nail never makes contact with the ground. Without that contact, the cat can't scratch to shed the nail sheath the way it normally would. The sheath builds up, the nail keeps growing, and it can eventually curl into the skin — becoming painful or infected.

Regular nail trimming is essential for these cats.