Turns out it’s nothing to do with water absorption and more to do with picking up slippery stuff.
U.K. researchers might have figured out one of the most enduring questions about human anatomy: Why do we get prune hands when sitting in the tub? A team at Newcastle University has concluded through experiments and testing that wrinkled fingers make it easier for humans to pick up wet, slippery objects. The researchers suggest in reports published in Britain’s Royal Society journal Biology Letters that as our distant ancestors searched for food in wet land and streams, the creases evolved.