hunting abilities as an aid in controlling shipboard rodents. Some sailors thought they bring good luck at sea. The rarity of polydactyl cats in Europe may be because they were hunted and killed based on superstitions about witchcraft. Genetic work studying the DNA basis of the condition indicates that many different mutations in the same ZRS area can all lead to polydactyly. Author Ernest Hemingway became a famous aficionado of polydactyl cats after a ship captain gave him a six-toed cat that he named Snow White. 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 50 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." Naming Nicknames for polydactyl cats include Hemingway cats, mitten cats, conch cats, boxing cats, mitten-foot cats, snowshoe cats, boston-toed cats, thumb cats, six-fingered cats, and Cardi-cats. Two specific breeds recognized by some cat fancier clubs are the American Polydactyl and Maine Coon Polydactyl. Breeding American Polydactyl cats are bred as a specific cat breed, with specific physical and behavioral characteristics in addition to extra digits. The American Polydactyl is not to be confused with the pedigree Maine Coon Polydactyl. The polydactyl form of the Maine Coon is being reinstated by some breeders. Genetics In the case of preaxial polydactyly of the Maine Coon cat (Hemingway mutant) a mutation of the cis-regulatory element ZRS (ZPA regulator sequence) is associated. ZRS is a noncoding element, 800 kilobasepairs (kb) remote to the target gene SHH. An ectopic expression of SHH is seen on the anterior side of the limb. Normally SHH is expressed in an organiser region, called the zone of polarizing activity (ZPA) on the posterior limb side. From there it diffuses anteriorly, laterally to the growth direction of the limb. In the mutant mirroring smaller ectopic expression in a new organiser region is seen on the posterior side of the limb. This ectopic expression causes cell proliferation delivering the raw material for one or more new digits. An identical sequence at this position serves the same function in human and mice and cause similar symptoms when mutated. Different mutations have different specific effects: for example, while the Hemingway (Hw) mutant tends to mostly induce extra fingers in the fore limbs, many other