A polydactyl cat is a cat with a congenital physical anomaly called polydactyly (or polydactylism, also known as hyperdactyly), which causes the cat to be born with more than the usual number of toes on one or more of its paws. Cats with this genetically inherited trait are most commonly found along the East Coast of North America (in the United States and Canada) and in South West England and Wales. Occurrence Polydactyly is a congenital abnormality that can be inherited in an autosomal dominant manner. Some cases of polydactyly are caused by mutations in the ZRS, a genetic enhancer that regulates expression of the sonic hedgehog (SHH) gene in the limb. The SHH protein is an important signalling molecule involved in patterning of many body elements, including limbs and digits. Normal cats have a total of 18 toes, with five toes on each fore paw, and four toes on each hind paw; polydactyl cats may have as many as nine digits on their front or hind paws. Both Jake, a Canadian polydactyl cat, and Paws, an American polydactyl cat, were recognised by Guinness World Records as having the highest number of toes on a cat, 28. Tigger, a tabby polydactyl cat, also had 28 toes, but passed before it could be verified by Guinness World Records. Various combinations of anywhere from four to seven toes per paw are common. Polydactyly is most commonly found on the front paws only; it is rare for a cat to have polydactyl hind paws only, and polydactyly of all four paws is even less common. History and folklore The condition seems to be most commonly found in cats along the East Coast of North America (in the United States and Canada) and in South West England, Wales and Kingston-upon-Hull. Polydactyl cats have been extremely popular as ship's cats. Although there is some controversy over whether the most common variant of the trait originated as a mutation in New England or was brought there from Britain, there seems to be agreement that it spread widely as a result of cats carried on ships originating in Boston, Massachusetts, and the prevalence of polydactyly among the cat population of various ports correlates with the dates when they first established trade with Boston. Contributing to the spread of polydactyl cats by this means, sailors were long known to value polydactyl cats especially for their extraordinary climbing and