Most cats have 18 toes — five on their front paws and four on their back ones — but some cats have a few extras, and they’re known as polydactyl cats.

A few more digits may not seem especially interesting, but there’s more to these many-toed cats than meets the eye.

1. Polydactyly is a genetic mutation.

It’s passed down through a dominant gene, so if one parent is polydactyl and the other has the normal number of toes, then 40 percent to 50 percent of their kittens will also have extra toes.

2. The condition is usually harmless.

Having extra toes isn’t unhealthy or detrimental in any way except that it can occasionally make trimming a cat’s nails more difficult.

However, there’s also a genetic condition known as feline radial hypoplasia in which extra toes are common, but it can actually be disabling because it causes underdeveloped or twisted forelegs.

3. Some polydactyl cats have 'mittens.'

“Mitten paws” occur when the extra toes are attached to the medial side of the cat’s paw, giving it a thumb-like appearance.

But while they may resemble a thumb, these extra digits aren’t opposable. Still, owners of such cats report that their kitties have pulled off feats such as opening latches and windows.

If you’re curious what the world would be like if cats actually had opposable thumbs, check out this video. To see some adorable kitten mittens in action, watch the video below.

4. Polydactyl cats without 'mittens' appear to simply have large feet.

This has earned them nicknames like “snowshoes paws,” “big-foot cats” and “pancake feet.”

5. Extra toes can be an asset for a cat.

“People like to see this because it’s quite cute … and for the most part, this is not an issue from a medical point of view. It’s just an interesting thing cats have that makes them a little more cute than they already are,” veterinarian Kelly St. Denis said in the documentary “Lion in Your Living Room.”

polydactyl catPhoto: brownpau/flickr

6. Polydactyl cats are more common in certain parts of the world.

Although the mutation can arise spontaneously in any cat population, the trait is most common in western England, Wales and the eastern United States and Canada.

The fact that populations of polydactyl cats are so widespread could be due to the cats’ popularity on ships.

7. Sailors believed many-toed cats were good luck.

Often called “gypsy cats,” these kitties’ large feet were thought to make them superior mousers, as well as provide better balance on the high seas.

8. There are some breeds of polydactyl cats.

These include the American polydactyl and the Maine Coon polydactyl, but cat fancier clubs doesn’t universally recognize such breeds.

9. Forty-percent of Maine Coon cats once had extra toes.

For a breed that originated in Maine, a state that sees more than 100 inches of snow annually in its northern interior, the wide paws function much like kitty snowshoes.

10. The Guinness World Record for most toes is 28.

A Canadian ginger tabby cat named Jake has seven toes on each paw, each with its own claw, pad and bone structure.

Ernest Hemingway and his sons play with kittens.Ernest Hemingway and his sons play with kittens. (Photo: Wikimedia Commons)

11. They’re known as Hemingway cats.

In the 1930s, a sea captain named Stanley Dexter gave Ernest Hemingway a polydactyl kitten born from his own cat, Snowball. The cat-loving author named the kitty Snow White, and that cat went on to parent numerous polydactyl kittens at Hemingway’s Key West, Florida, home.

As Hemingway wrote in a letter, “One cat just leads to another.”

Today, there are approximately 40 to 50 polydactyl cats — some of which are Snow White’s descendants — that live at the Hemingway House and Museum and are protected as a historical treasure.

The cats receive regular veterinary care, including vaccinations and treatments for fleas, heartworms and ear mites, and because Hemingway named all of his cats, the tradition continues today at his estate.

A polydactyl cat at Hemingway's houseA polydactyl cat at Hemingway's house (Photo: Wikimedia Commons)