The Finger Phenomenon
After spending a lengthy period in water, you may notice a particular phenomenon occur – wrinkled fingers and toes! A common misconception is that pruney digits are caused by water soaking into our skin, presumably by osmosis. In reality, furrowing in our fingers is caused by constricting blood vessels by the nervous system. But what could be the evolutionary purpose?
One hypothesis in 2011 was that that grooves in wet fingers would allow humans to grip surfaces more easily. Newcastle University researchers in England tested this theory, recording the time it took for subjects to move objects with dry fingers and with wet fingers. Every subject moved objects faster with wet fingers, suggesting that furrowed fingers can better handle moist items – an evolutionary advantage.
However, the study has not revealed how furrows improve grip. Neurobiologist Changizi from Idaho states that there may be other factors for improved grip, such as stickiness or oils. Scientists posit that the furrows may cause friction or increase flexibility. They also put forward a possible disadvantage of having pruney skin: grooves may decrease sensitivity or get caught on things. Further research to come!
What do you think about these theories?
Sources:
http://www.sciencenews.org/view/generic/id/347439/description/Pruney_digits_help_people_get_a_grip
henroids
When I got out of the shower today my fingers were wrinkled and personally I dislike the feeling that it brings, it just feels weird. But according to http://www.scientificamerican.com/article.cfm?id=why-do-our-fingers-and-toes-wrinkle-during-a-bath this wrinkling acts as treading just like we have on tires. When your fingers and toes wrinkle they provide a channel for the water to escape allowing for better griping of wet objects. This would allow for us to have better grip when walking on wet surfaces or handling wet objects, like the fruits and berries our ancestors gathered. This evolutionary advantage could have helped with survival way back when, but its only real practical purpose today might be just helping to make sure we don’t slip when getting out of a shower. Although personally I dislike the feeling that the pruneyness brings and prefer it when my fingers stay nice and unwrinkled.