Getting “pruney” or “wrinkly bath fingers” while doing the washing up or soaking in the bath can sometimes be annoying. But scientists have discovered there’s an evolutionary reason why that happens and why it helps us.
Researchers found that when skin puckers on fingers in water, itself due to the blood constricting which then pulls in the skin on fingers (or toes), that process actually helps us get a better grip on objects under water.
According to The Associated Press, even though recent research had shown that such puckering occurred as a nervous system response to water, the reasons why were unknown.
Until now that is.
A research team at the UK’s Institute of Neuroscience at Newcastle University, tested the usefulness of digit wrinkling on a group of human volunteers who were given wet objects to handle. What they found was interesting.
Under tests conditions, volunteers who had their hands immersed in warm water for 30 minutes were able to use their thumb and index finger to transfer glass marbles and lead fishing weights from one container to another, much faster than those with dry fingers.
Lead researcher, Tom Smulders, said of the study’s findings:
“We have shown that wrinkled fingers give a better grip in wet conditions. It could be working like treads on your car tyres which allow more of the tyre to be in contact with the road and gives you a better grip.”
Smulders told Agence France-Presse (AFP) that it was highly likely that wrinkling was an evolutionary advantage that possibly developed to allow for increased mobility on wet surfaces.
“This would explain why it happens to both hands and feet, and might have been an adaptation in some primate ancestor well before humans evolved, who might have walked on all fours.”
An enhanced ability to gather and handle food among wet vegetation, or water areas, or move around slippery ground easier could all have evolved from the need for humans to have those skills, Smulders adds.
“We use our hands for picking up objects but many other animals use their forepaws for walking and of course we get wrinkles on our toes as well. It is possible that it actually evolved to give better traction under wet conditions for running or walking.”
Oddly, the study found that wrinkling had no advantageous impact on the handling of dry objects, just wet ones, The Daily Mail notes.