Shrinking fingers have a function

The secret of the wrinkled fingers was revealed

10/01/2013

When our hands come into contact with water for longer, the skin becomes wrinkled. British researchers have now come to the bottom of this phenomenon. According to the study, wrinkled fingers or wrinkled fingers fulfill a purpose, because with wrinkled skin, wet objects can be gripped faster and better. For our primeval ancestors, this could have been an advantage in collecting food in bodies of water and wet vegetation, the researchers assume from an evolutionary point of view.

Wrinkled fingers work much like tire treads
Whether in the swimming pool, when washing dishes or under the shower - the skin is in contact with water for a longer period of time and begins to wrinkle on the hands and feet. Already in 2011, scientists dealt with this phenomenon. Mark Changizi and his team hypothesized that the wrinkled skin performs a similar function to that of a tire tread on cars that provides better grip on wet roads. The „profile“ Wet fingers also ensure that water can flow better, so Changizi.

Kyriacos Kareklas of Newcastle University and his team have recently provided scientific evidence for the benefit of wrinkled fingers, supporting Changizi's hypothesis as researchers in „Biology Letters of the British Royal Society report that shrinking fingers make it easier to grasp and transport wet objects, but for dry objects, the wrinkled skin would have neither the advantage nor the disadvantage.

The researchers suspect that the water is more easily drained by the wrinkles, so that the gripping ability improves. It is a misconception that fingers wrinkle when in contact with water because they swell up. „The formation of wrinkles is known to be an active process due to the control of the nervous system“, the researchers write. This suggests that the formation of wrinkled skin is not a simple reaction to the water, but rather involves a function.

Wrinkled fingers have a function
For their examination, 20 volunteers were to transport several glass marbles and small lead weights between index finger and thumb from one vessel to another. In one experiment, the objects were dry, in another wet. Both experiments were performed by the subjects once with dry hands and once with wrinkled hands, which were previously dipped in warm water for 30 minutes.

It turned out that the dry objects were always transported faster from one container to the other than the moist objects. It made no difference whether the subjects had wrinkled or non-wrinkled fingers. However, the wet objects were grasped and transported significantly faster with rune fingers by the study participants. „In this study we show - in accordance with the 'profile hypothesis' - that the skin folds improve the handling of wet objects“, so the researchers. „These results support the hypothesis that the wrinkles on the fingers formed by contact with water are an adaptation to the handling of moist objects and also provide the first empirical evidence for explaining a function of this known phenomenon.“

Wrinkled fingers for ancestors survival advantage
So far, it has not yet been clarified how exactly the skin folds allow a better grip. This must be further investigated, the scientists report. In addition to the hypothesis that the wrinkles better dissipate the water and thus improve adhesion, another possible explanation could be "found in the changing skin properties of wrinkled fingers that increase flexibility and grip." The wrinkled skin on the feet offers, according to the researchers, "a better grip".

Why the skin on hands and feet is not permanently shriveled, the researchers could not yet clarify. Finally, the skin folds have no disadvantage when handling dry objects, but a great advantage when gripping and transporting wet objects. According to experts, the wrinkled skin could potentially result in lower sensitivity and a higher susceptibility to injury.

From an evolutionary point of view, Tom Smulders, one of the authors of the study, suspects that „the crumpling of the fingers in the wet once helped to collect food from damp vegetation or from water bodies. "The wrinkled skin on the feet could have given stronger support in the rain. (sb)