I was wondering why our finger pads wrinkle when exposed to water for a certain time. The correct word for wrinkling here is prune. But lets just call it wrinkling. It turns out that this wrinkling process is actually evolutionary response to change in environment. The wrinkles help to increase our grip underwater.

Even though osmosis isn’t fully correct answer, it’s still an important factor. I searched and read many pages on this topic but none could answer it correctly. One of the closest correct answer would be –

“When hands are soaked in water, the keratin absorbs it and swells. The inside of the fingers, however, does not swell. As a result, there is relatively too much stratum corneum and it wrinkles, just like a gathered skirt. This bunching up occurs on fingers and toes because the epidermis is much thicker on the hands and feet than elsewhere on the body. (The hair and nails, which contain different types of keratin, also absorb some water. This is why the nails get softer after bathing or doing the dishes.)” – from ScientificAmerican.com