It's something that every child wonders at some point while splashing around in the bath or at a swimming pool: 'Why are my fingers all wrinkly?' The rest of your skin stays pretty much the same after a prolonged soak but your hands and feet take on prune like characteristics. I always assumed that your hands just absorbed the water and that caused the problem. I formulated this opinion before I knew much about biology and never really scrutinized this idea, which really doesn't stand up to much scrutinization.
But a cool bit of research (abstract below) has found that it's all to do with being able to handle wet objects better.WE have evolved a mechanism for improving how do things in the wet. Water being absorbed into the fingers isn't even a part of this phenomenon, as it's actually driven by the autonomic nervous system.The authors of the paper talk about theories as to why we don't have wrinkled fingers more often but the question I find interesting is why do we have them at all? Surely results like this tell us about our evolutionary past and the environments in which our ancestors lived and foraged. I have no idea if chimps, gorillas or orangutans have this adaptation. If they don't then it suggests it evolved after we diverged from our closest relatives. Ideas about humans foraging along the seashore have been a big part of understanding how humans evolved and spread out of Africa, so maybe this finding a clue to that?
A lot of this post is speculation, but that's the part of science that drives future areas of research and the joy of think about 'why?' is what I love so much about science.
Abstract:
Kareklas et al. (2013) Water-induced finger wrinkles improve handling of wet objects. Biology Letters
DOI: 10.1098/rsbl.2012.0999
Upon continued submersion in water, the glabrous skin on human hands and feet forms wrinkles. The formation of these wrinkles is known to be an active process, controlled by the autonomic nervous system. Such an active control suggests that these wrinkles may have an important function, but this function has not been clear. In this study, we show that submerged objects are handled more quickly with wrinkled fingers than with unwrinkled fingers, whereas wrinkles make no difference to manipulating dry objects. These findings support the hypothesis that water-induced finger wrinkles improve handling submerged objects and suggest that they may be an adaptation for handling objects in wet conditions.
http://rsbl.royalsocietypublishing.org/content/9/2/20120999
But a cool bit of research (abstract below) has found that it's all to do with being able to handle wet objects better.WE have evolved a mechanism for improving how do things in the wet. Water being absorbed into the fingers isn't even a part of this phenomenon, as it's actually driven by the autonomic nervous system.The authors of the paper talk about theories as to why we don't have wrinkled fingers more often but the question I find interesting is why do we have them at all? Surely results like this tell us about our evolutionary past and the environments in which our ancestors lived and foraged. I have no idea if chimps, gorillas or orangutans have this adaptation. If they don't then it suggests it evolved after we diverged from our closest relatives. Ideas about humans foraging along the seashore have been a big part of understanding how humans evolved and spread out of Africa, so maybe this finding a clue to that?
A lot of this post is speculation, but that's the part of science that drives future areas of research and the joy of think about 'why?' is what I love so much about science.
Abstract:
Kareklas et al. (2013) Water-induced finger wrinkles improve handling of wet objects. Biology Letters
DOI: 10.1098/rsbl.2012.0999
Upon continued submersion in water, the glabrous skin on human hands and feet forms wrinkles. The formation of these wrinkles is known to be an active process, controlled by the autonomic nervous system. Such an active control suggests that these wrinkles may have an important function, but this function has not been clear. In this study, we show that submerged objects are handled more quickly with wrinkled fingers than with unwrinkled fingers, whereas wrinkles make no difference to manipulating dry objects. These findings support the hypothesis that water-induced finger wrinkles improve handling submerged objects and suggest that they may be an adaptation for handling objects in wet conditions.
http://rsbl.royalsocietypublishing.org/content/9/2/20120999
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