Hemingway lived in Key West through most of the 1930s, writing some of his best-known work there. At some point a ship’s captain gave him a white polydactyl kitten — extra toes, usually on the front paws, sometimes the back too. Hemingway’s sons named her Snow White.

Snow White never left. Neither did her descendants.

The house became a museum in 1964, and the cats simply stayed on as permanent residents. Today the Hemingway Home & Museum counts roughly 57 of them, and about half still carry the visible six-toed trait. The other half look like ordinary cats on the outside, but here’s the twist: every single one carries the polydactyl gene, extra toes or not, which means a perfectly normal-looking four-toed cat can still turn around and produce a litter of six-toed kittens.

Polydactyly isn’t a breed. It’s just a trait that shows up across tabbies, calicos, tortoiseshells, black cats, white cats, basically anything with a coat. The museum’s cats come in every color combination you’d expect from a normal colony — they just happen to have a few bonus toes tucked in the mix.

There’s a reason polydactyl cats were especially popular on ships, and it has nothing to do with luck, or at least not directly. Extra toes work like built-in snowshoes, giving a cat better grip and balance on a rocking, wet deck — genuinely useful when your job is catching mice on something that won’t stop moving. Sailors noticed, decided the cats were good luck, and kept them aboard. Somewhere down that maritime chain, the captain who gave Hemingway his kitten was just continuing the tradition.

One more thing the museum kept going: Hemingway named all his cats after celebrities, and the staff still does. So the polydactyl cat sunning itself on the veranda today might be named after someone who has absolutely no idea a six-toed cat in Florida is currently wearing their name.