Why do we wrinkle when wet? whenever our fingers and toes get wet for more than about 10 minutes, they go wrinkly. It was previously thought that we wrinkled when we got wet because of absorption, which would expand the surface area of the skin, making it appear wrinkly. but it turns out its actually all to do with our nervous system.
In 1935 it was noticed that patients with nerve damage in their extremities didn’t exhibit this reaction to getting their fingers and toes wet. In one case, a boy had 3 damaged fingers, and while all other digits went wrinkly, the 3 suffering nerve damage stayed smooth and unaffected. This led to the discovery that wrinkly skin is not caused by excess moisture absorption, but by a nervous response to being exposed to moisture for a prolonged period of time.
When the skin gets wet for a while, the sensory receptors on the end of our fingers and toes send signals to the brain, which responds by constricting the blood vessels just below the surface of the skin, causing the skin to wrinkle. As this response is involuntary, there must be an evolutionary reason for it.
To find out why the body does this and what benefits it could have scientists do what they always do, they experimented. In 2013 test subjects were asked to pick up objects out of water with both wrinkly and non wrinkly fingers. It was found that patients who had undergone this nervous response that they could pick up objects 12% faster than those without it. The wrinkles were diverting and channelling the water away from the objects as the subjects went to pick them up.
So there you have it, though annoying when you’ve just got out of the bath, the reason you can pick things up underwater is all down to the wrinkles on our skin.