起皱的手指不湿滑

After a long bath, your fingers and toes come out all wrinkly. You may have wondered why your skin would go and do such a thing. Now a study shows that puckered digits give us a surer hold on objects that are slippery when wet. This gripping discovery appears in the Royal Society journal Biology Letters. [Kyriacos Kareklas, Daniel Nettle and Tom V. Smulders, Water-induced finger wrinkles improve handling of wet objects]

It might seem like magic, or maybe osmosis, that sets your fingertips rippling after being submerged for awhile. But it’s actually an active process that’s controlled by the same part of the nervous system that regulates your heartbeat, breathing and even sweat. So, underwater wrinkling is something your body does on purpose.

To explore the potential advantages of waterlogged fingertips, researchers asked volunteers to move a bunch of marbles from one bucket of water to another. Sometimes their fingers were wrinkled, sometimes they were smooth. The results: subjects were more nimble with the wet marbles when their fingers were wrinkled.

Could be that this mechanism gave our ancestors a leg-up, or hand-up, when it came to grabbing wet fruit or dashing through the rain. Now science has shown that wrinkled fingers also help keep us from losing our marbles.

—Karen Hopkin