Animals Pets 8 Things You Didn't Know About Polydactyl Cats By Laura Moss Writer University of South Carolina Laura Moss is a journalist with more than 15 years of experience writing about science, nature, culture, and the environment. our editorial process Laura Moss Updated December 27, 2020 Ed-Ni-Photo / Getty Images Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species Polydactyl cats are those with more than a standard number of toes. Some have more than five on their front paws, or, less often, more than four on their hind feet. The condition 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 through a dominant gene, meaning 40 to 50 percent 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. Polydactyl Cats Have Either 'Mittens' or 'Snowshoes' Photo by Laurie Cinotto / Getty Images 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. 3. Their Extra Toes Can Be an Asset Apart from being exceedingly cute, widely adored for their superfluous digits, polydactyl cats have also in the past been perceived as good luck symbols. Contrary to their all-black feline counterparts, "gypsy cats" — as they were known — were once highly respected and coveted by sailors, who believed them to be superior mousers and best fit for balancing on the high seas. 4. They're More Common in Certain Parts of the World Although the mutation can arise spontaneously in any cat population, the trait is most common in the U.K., U.S., and Canada, a 2020 study published in SAGE Journals says. 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. 5. 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 of these are universally recognized cat breeds. The Maine Coon cat is said to have had extra digits for getting around in Maine's abundance of snow. 6. 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. 7. 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 is 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. 8. 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.