Why We Get Prune Fingers

Evolution explains: wrinkled fingertips give us a better grip on wet things. Like built-in traction gloves.

prune giners 615.jpg.jpg
quinn.anya/flickr

Here's a dinner party fact. If you were to soak a severed hand in a bucket of water, it wouldn't develop prune fingers. That's right, because finger prune-wrinkling is a nervous system response, not just some osmotic result of our skin absorbing water like a wet potato. 

We've known that for a long time, but until this week, we didn't know exactly why that autonomic response existed. 

meritbadgeman.jpgsteve.garner32/flickr; superfantastic/Flickr

The 2011 journal article "Are wet-induced wrinkled fingers primate rain treads?" suggested that prune fingers work like car tires. The wrinkles channel water off of our fingers, so we get better traction on things we want to hold. But that was just their theory from the way it looks; they didn't actually test that it worked.

This week, research in the journal Biology Letters, proved that people with water-wrinkled fingers were indeed faster at picking up wet marbles.

So, as evolution would have it, our ancestors who were not as good at picking up marbles were less likely to be chosen as suitable mates and pass along their genes. Or, actually, the ones who weren't as good at hand fishing and clam digging and those sorts of things after their hands were all wet and slippery; they wouldn't thrive and reproduce. The prune-fingered people, meanwhile, flourished and feasted and were the eminently desirable.

Our toes wrinkle in water, too; don't forget. (Did you forget about your toes?) The researchers deduce that toe wrinkling is, similarly, to help us get traction when we're walking/running on wet surfaces. Which is interesting, because we're still not that good at it.

Presented by

James Hamblin, MD, is a senior editor at The Atlantic. He writes the health column for the monthly magazine and hosts the video series If Our Bodies Could Talk.

How to Cook Spaghetti Squash (and Why)

Cooking for yourself is one of the surest ways to eat well. Bestselling author Mark Bittman teaches James Hamblin the recipe that everyone is Googling.

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register.

blog comments powered by Disqus

Video

How to Cook Spaghetti Squash (and Why)

Cooking for yourself is one of the surest ways to eat well.

Video

Before Tinder, a Tree

Looking for your soulmate? Write a letter to the "Bridegroom's Oak" in Germany.

Video

The Health Benefits of Going Outside

People spend too much time indoors. One solution: ecotherapy.

Video

Where High Tech Meets the 1950s

Why did Green Bank, West Virginia, ban wireless signals? For science.

Video

Yes, Quidditch Is Real

How J.K. Rowling's magical sport spread from Hogwarts to college campuses

Video

Would You Live in a Treehouse?

A treehouse can be an ideal office space, vacation rental, and way of reconnecting with your youth.

More in Health

Just In