The Hemingway Cats are a colony of polydactyl cats maintained at the Ernest Hemingway Home and Museum in Key West, Florida. Many visitors to the museum enjoy interacting with the cats, a living legacy of Hemingway's cat-loving personality, and the staff at the museum are responsible for maintaining the health and welfare of the cats, under the terms of Hemingway's will.
These famous felines are descended from Snowball, a six-toed cat given to Hemingway while he lived in Key West. Snowball apparently came from a ship's captain, and while living on Key West, the cat sired a number of offspring, all of which also exhibited the trait of polydactyly. Many of the Hemingway Cats are descendants of the original Hemingway Cat, and the cats come in a wide range of colors and sizes, with various degrees of polydactyly from a single extra toe to several extra digits.
Because Key West is an island, it is assumed that most of the cats on the island are probably relatives of the Hemingway Cats, and there is a high rate of polydactyly on the island beyond the community of the Hemingway Cats to support this theory. The Hemingway Cats have also been the cause of some controversy, with some island residents being concerned about their welfare, while others have resisted the presence of the cats, because they have historically been allowed to run wild on the island and stir up trouble with local felines.
In response to criticisms about the treatment of the Hemingway Cats, the staff of the Hemingway Museum have made some efforts to contain them, including the institution of a spay and neuter program to keep the population of Hemingway Cats to around 60. The cats also receive regular routine veterinary care from a visiting veterinarian, and flea control products are used to prevent the spread of fleas. The cats are also confined on-site as much as possible.
At one point, members of the public were able to adopt cats from the Hemingway clan, although this is not longer permitted, due to the spay/neuter program which has kept the population under tighter control. However, it is entirely probable that numerous offshoots of the famous cat colony can be found in other regions of the United States, passing on their polydactyly to their local communities. Given that polydactyly is already a common mutation on the Eastern Seaboard of the United States, some areas probably have a mutation rate which is so high that it has become common.