Wrinkles on fingers appear beneficial for gripping wet objects

Science : When it was discovered that the formation of wrinkles on wet fingers is triggered by nerve signals, neuroscientists proposed that the grooves help us grip wet objects. Tom Smulders of Newcastle University in the UK and his colleagues believe they’ve confirmed that hypothesis. The researchers compared the ability of test subjects to perform manual dexterity tasks with wrinkled and nonwrinkled hands on both wet and dry objects. They found that wrinkled hands gave a 12% speed increase over smooth hands with wet objects, but no benefit when handling dry objects. Their research mirrors similar tests by other researchers, though none of the experiments examine how wrinkles improve grip. Other than channeling water, which prevents hydroplaning, wrinkling may also increase contact surface area or contribute to loss of oil on the skin. And it also isn’t clear whether wrinkling evolved to provide a benefit in gripping, or whether it is just a biomechanical quirk. Smulder says that further experiments may also reveal downsides to long-term wrinkling, or whether wrinkling of the feet and toes provides a benefit when walking on wet surfaces.