A polydactyl cat is born with more than the usual number of toes on one or more of its paws. Normal cats have a total of 18 toes, with five toes on each front paw and four toes on each hind paw; polydactyl cats may have as many as eight digits on their front and/or hind paws. Jake, a Canadian polydactyl cat with 28 toes, was recognised by Guinness World Records as having the highest number of toes on a cat. 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.
Populations of polydactyl cats are found in port towns, probably 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 hunting abilities as an aid in controlling shipboard rodents. Some sailors also considered them to be extremely good luck when at sea.
Ernest Hemingway was a famous lover of polydactyl cats, after being first given a six-toed cat by a ship’s captain. Upon Hemingway’s death in 1961, his former home in Key West, Florida, became a museum and a home for his cats, and it currently houses approximately fifty descendants of his cats (about half of which are polydactyl). Because of his love for these animals, polydactyl cats are sometimes referred to as “Hemingway Cats”.
Nicknames for polydactyl cats include “conch cats“, “boxing cats“, “mitten cats“, “mitten-foot cats“, “snowshoe cats“, “thumb cats“, “six-fingered cats“, “Cardi-cats“, and “Hemingway cats“. (paraphrased from Wikipedia)