Here’s what Professor Hallux has to say:
It’s certainly a weird one but scientists have come up with a few ideas to explain this crinkly conundrum.
You might think it’s the water soaking into your skin but that’s not true! If it was, all your skin would go crinkly when wet. Studies showed that peoples’ fingers didn’t wrinkle if the nerves in their fingers were damaged so it’s thought that when moisture is detected, your nervous system tells your blood vessels to contract, creating the bumpy surface.
The theory goes that having creases on your fingers and toes makes it easier to pick things up in slippery wet conditions. Just like the treads on your trainers, those wrinkles help you get a grip. It could be that ancient ancestors of human beings – the cavemen, might have found it really important to be able to pick up food or use tools under water. But I don’t want to hear of you lot using tools in the bath – stick to a flannel and a rubber duck!