Why Do Polydactyl Cats Have That Extra Toe?

Did you know that the Ernest Hemingway Home and Museum in Key West, Florida, the majestic residence where the writer lived in the 1930s, and where he wrote The Snows of Kilimanjaro, among many more of his most beloved works, is inhabited by almost five dozen cats? An even more fun fact: many of them have an extra toe.

Sadly, I have not yet been there to count the kitties myself, but about half of them have six toes on each of their front feet (some have them on their back feet, too). “Sometimes, it looks as if they are wearing mittens because they appear to have a thumb on their paw,” the website says. 

How did this happen? Apparently, a ship’s captain gave Hemingway a six-toed cat, whom he named Snow White, and all of the cats on the house and museum grounds today are her descendants. Although not all of them have extra toes, they all carry the gene for “polydactyly,” the name of the genetic mutation that causes this quirk. Although they are all called polydactyl cats, it doesn’t mean they’re all the same breed of cat.

On What If Cats Had Opposable Thumbs Day, it was only fair to spotlight these felines (though polydactyl toes are not necessarily opposable, to be clear — more on that later). So, I asked veterinarian Dr. Clara Whitmore, in-house advisor at Boxie Cat, to explain what polydactyl cats do with that extra toe, besides look adorable.

How do cats get extra toes, and how do they use them?

“The polydactyly mutation follows an autosomal dominant pattern of inheritance, which means a cat has only to inherit one copy of the gene from a parent to express the trait,” Dr. Whitmore explains. “The most common incidence of polydactyl cats is in certain breeds, such as the Maine Coon, but they can occur in any cat.” She says cats with the polydactyly gene develop extra toes on any of their paws — it could be just one, or it could be all of them. “Interestingly, these extra toes usually do not affect the health of the cat, though they sometimes are more pronounced than in other cats and make the paws look even more distinctive.”

It’s long been rumored that the somewhat mystical Anne Boleyn, the second wife of King Henry VIII, had an extra finger on her left hand, though it’s not officially documented. And look what happened to her. Maybe her alleged scandalous life, rumored association with witchcraft, and her execution by beheading didn’t have anything to do with that fabled sixth finger. But still: Do polydactyl cats have any special, perhaps magical, traits?

They don’t necessarily have any magical traits, says Dr. Whitmore, but practical advantages? Yes. She says that depending where the extra toes are located, they can be useful. “For example, the additional toes on the front paws can often act almost like an opposable thumb, which enables the cat to grasp things with much more dexterity. This could be particularly helpful in climbing or holding onto things.” Most of the time, though, the extra toes are strictly a cosmetic feature. “[Extra toes] do not afford them much extra advantage, though they are part of what makes polydactyl cats so special,” Dr. Whitmore says.

What else does the extra-toe trait mean?

An extra toe bean, in itself, is a wonderful thing. But is there anything else remarkable about polydactyl cats — the ones living at Hemingway’s home, or anywhere else? “Other than the additional toes, there are usually no other unusual characteristics associated with polydactyly,” Dr. Whitmore says. “These cats are no less healthy or capable than their non-polydactyl brethren, and there are no specific health concerns linked to the extra digits.” 

If you’re lucky enough to have a polydactyl cat, it’s a good idea to have their toes checked out by a veterinarian now and then, as they can sometimes cause trouble. “On occasion, if the extra toes are not well-developed, they may cause some discomfort or need to be trimmed to prevent injury,” Dr. Whitmore adds. “But for the most part, polydactyl cats lead normal, active lives.” 

I don’t know about you, but I feel like this is a good time to book a trip to Key West. I need to research these six-toed cats for myself — and counting toe beans while lounging in the sun sounds pretty good right about now.

References

• “Anne Boleyn: Temptress, Witch, or Six-Fingered Heroine? Whynow.” Whynow, 5 July 2023, whynow.co.uk/read/anne-boleyn-temptress-witch-or-six-fingered-heroine. Accessed 3 Mar. 2025.

• hemingwayhome.com. “Hemingwayhome.com | Home.” Hemingwayhome.com, 2019, www.hemingwayhome.com/.