I have had a fascination of Hemingway cats for years. Now I have two, one male, one female. Many people are not aware of this genitic mutation. and there origin.

Many-Toed Polydactyl Cats
Ernest Hemingway was an amazing man, with many talents and interests. He was also an inveterate cat-lover, because he admired the spirit and independence of cats. Hemingway acquired his first cat from a ship's captain in Key West, Florida, where he made his home for a number of years. This cat, which may have been a Maine Coon, had extra toes (technically known as polydactyl, latin for "many digits"). Today, approximately 60 cats, half of them polydactyl, make their home in the Ernest Hemingway Museum and Home, in Key West, protected by the terms of his will. At least some of those cats are descendents of Hemingway's first cat, and are given fanciful names, as he once did, after movie stars and even characters in his book. The cats of the Hemingway Museum are so popular and so well-known, that the nickname "Hemingway Cats" has often been given to polydactyls.

What is Polydact?
The trait for polydact comes from a dominant gene, and only a polydactyl cat can parent another polydact. Although the Maine Coon (whose ancestors are also thought to have immigrated to the U.S. aboard ships) is believed to have been the first breed to have this trait, polydact is considered a fault in that breed, and indeed in every other breed except the Pixie Bob, a relatively new breed.
So, rather than a breed, polydact is just a genetic trait, somewhat like the genetics for the tabby pattern. Instead of the normal 18 toes (five on each front foot and four on the rear) found on most cats, polydacts have six or more toes on the front feet, and sometimes an extra toe on the rear. (The cat depicted in the photo has seven toes in front, which makes it easy to understand why they are sometimes called "Mitten Cats.") However, unlike the popular tabby, whose pattern can be found in many breeds, the polydact is frowned upon by breed registries. Why? According to Barbara French, although not inherently dangerous, there is a possibility that the extra toes could be malformed, either with two toes fusing, or with ingrown toenails.
Although not approved as "purebreds," polydacts are adored by their human companions. Whether called "polydactyls," "Hemingway Cats," or "Mittens," these many-toed cats warm the hearts and hearths of those people fortunate to share a home with one.