A Genetic Anomaly in Cats

HIstory of the Thumb Cats, Hemingway and Mitten Kittens

Polydactyly is a type of genetic mutation that causes cats to be born with more than usual number of toes.

The first scientific record of the polydactyly genetic trait was in 1868. These many toed cats became infamous as hunters and climbers, making them a welcome guest upon any ship. Folklore even says that the extra toes made them more adaptable to the unbearable sway of the ship on the high seas and that they brought sailors good luck.

Ernest Hemingway became a fan of these "Mitten Kittens" when a ship's captain gave him a six-toed cat. The descendants of these cats still live in his Key West Home. They have even sparked a bit of controversy in the media over the federal government's involvement in regulation of these cats.

How the Disorder Works


Polydactyly is a congenital mutation that is autosomal dominant in inheritance of the Pd gene. The occurance of anywhere between four and seven toes on each paw is most common, with the Guinness World Record holder having 28 toes total (up from the normal 18 toes).

Associated Problems

Common problems with Polydactyl cats are associated with the nail, nail trimming or lack thereof. This could lead to the nail growing into the pad of the paw, creating an infection. If you have a polydactyl cat, it is important to get your cat inspected by your Veterinarian for the proper toe count.

At left: A radiograph showing the bone structure of a polydactyly cat.


Photo 1, Black Ernest Cat: 2007-02-12 19:13 Averette 2048×1536×8 (1959371 bytes) Digital photo taken by Marc Averette. Polydactyl cat at [[Ernest Hemingway House]] in [[Key West, Florida]] on 2/10/2007. {{pd-self}}

Chapman, VA; Zeiner, FN: The anatomy of polydactylism in cats with observations on genetic control Anatomical Record 141:205-217, 1961

The Christian Science Monitor: www.csmonitor.com

Cat uses extra toes like thumb to hold pen