10 Things You Didn't Know About Polydactyl Cats

A polydactyl cat, which may also be called a six-toed cat, is one that is born with more toes than usual. Some polydactyl cats have more than five on their front paws, or, less often, more than four on their hind feet. This scenario is common (at least among the feline variety) and is actually caused by a genetic mutation. However, said mutation doesn't hinder the cat. In fact, it's believed to make them especially cute and, historically, good luck.

Learn more about these extra extremities—such as how many the Guinness World Record holder has—and how they may impact the life of your cat.

1. Polydactyly Is a Genetic Mutation

The condition that causes a cat to have extra toes is caused by a genetic mutation, albeit not usually a harmful or unhealthy one. Polydactyly, also known as hyperdactyly or hexadactyly, is passed down as an autosomal dominant trait, meaning 40 to 50% of a litter is likely to be born with extra toes if just one of the parents is polydactyl. Although the congenital physical anomaly is usually harmless, it can also be a side effect of other genetic conditions like feline radial hypoplasia, which can cause underdeveloped or twisted forelegs, disabling the cat.

2. They Were Once Adored by Hemingway

According to the Ernest Hemingway Home & Museum, a sea captain named Stanley Dexter gave the writer a polydactyl kitten born from his own cat, Snowball, during the '30s. The cat-loving author named it Snow White, and that cat went on to parent numerous polydactyl kittens at Hemingway’s Key West, Florida, home. “One cat just leads to another,” he once wrote.

Today, there are about 40 to 50 polydactyl cats—some of them Snow White’s own descendants—that still live at the Hemingway Home & Museum and are protected as historical treasures. His affection for extra-toed felines is the reason why polydactyl cats are often called "Hemingway cats" today.

3. Polydactyl Cats Have Either 'Mittens' or 'Snowshoes'

There are three kinds of polydactyly: Postaxial is where the extra digits are on the exterior (pinky) side, preaxial is where the extra digits are on the medial side, and mesoaxial (very rare) is where extra digits are central in the hand or foot. Cats with postaxial and mesoaxial polydactyly are often said to have "snowshoe paws" or "pancake feet" because of their wide-set paws. Cats with preaxial polydactyly, on the other hand, are called "mitten cats" or "thumb cats" because their spare toes have a thumb-like appearance. Of course, they still aren't opposable.

4. Their Extra Toes Can Be an Asset

Having extra toes may at times be a hinderance—namely because it increases the risk of snagging a claw—but there are also benefits to having wider paws. For instance, one polydactyl cat, Cravendale, from Warrington, England, was known to use his four extra toes to pick up toys and climb like a human. Their extra digits afford them a better grip on treats and help them navigate challenging surfaces, like sand or snow. What's more, polydactyl cats are thought to have an easier time catching and holding prey as they hunt.

5. They're More Common in Certain Parts of the World

According to a 2020 study published in SAGE Journals, there are three genetic variants that are responsible for polydactyly, and these variants have been found specifically in cats located in the U.K. and the U.S. The fact that populations of polydactyl cats are so widespread and concentrated around transatlantic ports of call (for instance, Maine, Wales, and Western England) could be due to the cats’ supposed prevalence on cargo ships.

6. There Are Entire Breeds of Polydactyl Cats

Polydactyly is so common in cats that it has given way to entire breeds, such as the American polydactyl—bred not just for extra toes but also other physical and behavioral characteristics—and the Maine coon variety, though neither are universally recognized cat breeds. The Maine coon cat is said to have used its extra digits to get around in Maine's abundance of snow.

7. But Cats Aren't the Only Species With Extra Digits

Polydactyly is common in cats, yes, but the condition can also be found in dogs, mice, chickens, guinea pigs, and even llamas, foals, and other hoofed livestock, proving that it isn't unique to mammals nor to digitigrades. It's also one of the most common congenital limb malformations in humans, affecting one in approximately 700 to 1,000 live births (twice as common as syndactyly, which causes a fusion of digits). It is often treated by removing the extra finger or toe during early childhood.

8. They Can Have Many Extra Toes

Cats can have several extra toes on each foot, though they are more likely to have them on their front paws than they are to have them on their hind paws. Extra toes on both forepaws and hind paws are even rarer, research says. A Canadian ginger tabby cat named Jake with seven toes on each paw—28 in total—holds the Guinness World Record for "most toes on a cat." Each digit has its own claw, pad, and bone structure.

9. Cat Polydactyly Was First Mentioned More Than a Century Ago

The earliest scientific record of feline polydactyly was in the 19th-century Burt Green Wilder papers, one of which he titled, simply, "Extra Digits." Wilder was a comparative anatomist who graduated from Harvard University and went on to teach at Cornell. His papers, published from 1841 to 1925, covered a diverse range of topics, from family genealogy to spiders, but according to the Cornell archives, Wilder had a penchant for researching cats. As many as 400 cats were used for his studies each year. The paper he wrote describing feline polydactyly was published in 1868.

10. They Were Considered Good Luck Charms

There are a couple theories on where polydactyl cats originated. Some say they all descended from the Maine coon cat, native to North America (particularly the northeastern state after which it's named), while others say these extra-toed animals were brought over by English Puritans in the 1600s. If the latter is true, that could be why the cat is so deeply rooted in nautical folklore.

Contrary to their all-black feline counterparts, these cats have long been perceived as good luck charms. They were once highly respected and coveted by sailors, who believed them to be superior mousers and best fit for balancing on the high seas. It's perhaps because of their popularity on said transatlantic travels that they are now so much more common in old port cities.