Surely you’ve noticed that when taking long baths, shower or wash the dishes in the kitchen, your fingers become wrinkled. This phenomenon has repeatedly provoked scientists to research and find out the reasons.
One of the oldest theories was that the wrinkling of the fingers is a consequence of the absorption of water from the outer layer of the skin. Namely, scientists have believed for decades that the epidermis was increasing its area and then it wrinkles because the bottom layer is glued to it, which prevents it to expand more.
Laboratory tests showed that this phenomenon does not occur when one of the nerves in the fingers is damaged. According to them, this is a result of the contraction of blood vessels or in other words, this is a reaction that is controlled by the sympathetic part of the nervous system. Neurologists see an evolutionary reason for this.
The year 2013 proved to be crucial for this phenomenon. At that time, the scientists from Newcastle University in the UK did experiments to prove that thanks to the wrinkles on the fingers and toes, one can grip on wet surfaces. The trials involved people with completely dry hands and ones who have kept them for more than 30 minutes in water to wrinkle. It turns out that the latter were able to complete the tasks much more quickly than the other participants. Quite the contrary happened when they had to move dry items. Then it became clear that the non-wrinkled fingers cannot provide the necessary advantage.
“If a function of the body is controlled by the nervous system only in certain cases, it can be assumed that this function has been selected in the process of evolution. And evolution would not have chosen it if it didn’t have an advantage”, says Tom Smolders from the Centre for Behaviour and Evolution at the University of Newcastle.