Scientists think that they have the answer to why the skin on human fingers and toes shrivels up like an old prune when we soak in the bath. Laboratory tests confirmed a theory that wrinkly fingers improve our grip on wet or submerged objects, working to channel away the water like the rain treads in car tires.
People often assume that wrinkling is the result of water passing into the outer layer of the skin and making it swell up. But researchers have known since the 1930s that the effect does not occur when there is nerve damage in the fingers. This points to the change being an involuntary reaction by the body's autonomic nervous system — the system that also controls breathing, heart rate and perspiration. In fact, the distinctive wrinkling is caused by blood vessels constricting below the skin.
To read the original article: Why Do Our Fingers and Toes Wrinkle During a Bath?: Scientific American
