Pruney Fingers Get Better Grip: Wrinkles May Be Evolutionary Adaptation to Wet Conditions
Lewis, Tanya, Science News
Scientists have an answer to the pressing question of why hands and feet get wrinkled after too much time in the bath: Pruniness may have evolved to make it easier to grip wet objects.
Though often assumed to be a result of water passively seeping into the skin, the phenomenon is actually caused by the nervous system constricting blood vessels. But what evolutionary purpose wrinkling serves, if any, has been a mystery.
In 2011, researchers proposed that the grooves in wet fingers might function as "rain treads" that improve grip by channeling water away, much as car tires on a wet road do. Toes wrinkle too, which could have evolved to provide surer footing on slick surfaces. Now, researchers at Newcastle University in England have tested the rain-tread theory.
The researchers had 20 volunteers manipulate objects with smooth fingers or digits shriveled by immersion in warm water. The experimenters measured how long it took people to transfer the objects between a water-filled container and a dry one, or between two dry ones, with wrinkled versus unwrinkled fingers. …