Sunday Trivia: Polydactyly


As I am leaving town for a week tomorrow morning, but still have some time on my hands today, I wanted to post something which folks might find entertaining, but was unlikely to result in a flurry of argument which would need my attention. Therefore, I am writing what people always write in moments like these: trivia.

Do you know about polydactyl cats? I didn’t, until my son realized that the kitten we were planning on adopting had “mittens” for feet. Sure enough…the cat has thumbs. All the females in the litter did, as well as the Mom. Intrigued (and more than a little overwhelmed by how cute it is), I set out to do some research.

Polydactyly in cats is actually fairly common in the eastern U.S. and western Europe. They have been around for centuries, and were actually considered lucky by sailors (hence the coastal spread, I suppose). Despite what my vet told me, it turns out that many of these cats actually can use their “thumbs”–they are opposable! Scary, you say? Well, a little. I haven’t trained the kitten to make coffee, yet, though….

Polydactyly is also known to exist occasionally in large cat species. Take just a minute and imagine a lion with opposable thumbs…*smile* I feel all better, don’t you? The trait can occur as both a genetic one (passed down from parent to child, and in my kitten’s particular case, apparently sex-linked) or as a random mutation. One of the most fascinating things about polydactyly, however, is that when genetic, it appears to simply transmit the message of “add one more” to the toes, so that if you have breeding between two polydactyl cats, each generation winds up with one more toe than the last. There are reports of cats having up to twelve toes on each foot! Sadly, at that point, they tend to be somewhat crippled…so the trait dies out.

Most polydactyl cats have extra toes on their front feet, only, though some (like mine) have them on the back, as well. In Morgan’s case, she has two dew claws in the back. Further, her front feet actually have two extra claws on each “thumb”, with the innermost one seemingly not retractable. She taps when she walks. *smile*

Bonus Trivia: Polydactyl cats are also called “Hemingway cats”, because Ernest Hemingway had an island off of Florida where he let the cat population breed to its (collective) heart’s content. The polydactyl cats outbred the “normal” ones, and before long all the cats on the island had thumbs.