Why do fingers wrinkle in water, and it's not because they 'soak up' like a sponge?

This isn't because your skin swells up by absorbing water, but rather your nervous system's active 'anti-slip technology' at play! Many people have always believed that fingers wrinkle because the skin absorbs water like a sponge, causing it to swell and deform. However, medical research has long debunked this myth: if the nerves in your fingers (like the median nerve) are damaged, your skin won't wrinkle at all, no matter how long you soak them! In reality, when skin is exposed to water for an extended period, moisture seeps through the sweat gland ducts, stimulating the nerve endings beneath the skin. These nerves report to the sympathetic nervous system and issue a precise command: to immediately constrict the blood vessels under the skin of your fingers (Vasoconstriction)! When the blood vessels constrict, the volume inside the finger decreases, and the outer skin loses its support, passively pulling and contracting into regular wrinkles. Scientists have found that these wrinkles, much like the 'tread patterns' on car tires, help us quickly channel water away in wet, slippery conditions, making it easier to grip objects!