The early-primate to early-hominoid hands probably had relatively long thumbs, similar to humans. Chimps do not have very long thumbs and yet they can easily pick up a needle from the ground. have even longer thumbs comparatively and they are not significantly "highly dextrous". It has been argued that this was an evolutionary response to our need for higher dexterity. Human hands are distinguished from apes by possessing longer thumbs relative to fingers, and broader palms. This suggests that wrinkles serve the function of improving our grip on objects under water, or wet objects in general. Our fingers and toes become wrinkled when they are wet for extended periods of time. Tom Smulders explains his findings that people are faster at moving objects taken out of water if their fingers are wrinkled than if they are not. The analogous effect in the toes could help us to get a better footing in the rain. Wrinkled fingers could have helped our ancestors to gather food from wet vegetation or streams, Smulders adds. "We have shown that wrinkled fingers give a better grip in wet conditions - it could be working like treads on your car tires, which allow more of the tire to be in contact with the road and gives you a better grip," says Tom Smulders, an evolutionary biologist at Newcastle University, UK, and a co-author of the paper. In fact, the distinctive wrinkling is caused by blood vessels constricting below the skin.īack in 2011 Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, had suggested that the purpose for wrinkly fingers and toes might have an evolutionary function and the latest experiments have shown that wrinkly fingers do in fact help test subjects grip wet objects far more effectively than dry objects (for which there is no noticeable difference). This shows that the change is an involuntary reaction by the body's autonomic nervous system - the system that also controls breathing, heart rate and perspiration.
CHIMPANZEE HAND FINGERS SKIN
It is often wrongly assumed that wrinkling is the result of water passing into the outer layer of the skin and making it swell up, but researchers have known since the 1930s that the effect does not occur when there is nerve damage in the fingers. Laboratory tests confirmed that wrinkly fingers improve our grip on wet or submerged objects, probably working to channel away the water like the rain treads in car tires. In January 2013 scientists discovered a possible explanation for why the skin on human fingers and toes shrivels up like an old prune when we soak in the bath. A Brief History and Key Proponents of AAT
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