[sci/bio] Whoa: water wrinkles not from absorption
(h/t Metafilter)
From The Best Facts I Learned from Books in 2015 by Kathryn Schulz: Why do your fingers and toes turn all pruney after soaking in water? I’d assumed that the answer was osmosis, until I came across the real explanation in Cynthia Barnett’s “Rain.” Since the nineteen-thirties, Barnett writes, researchers have known that people with nerve damage in their arms don’t develop water wrinkles in their fingers; subsequent scientists discovered that the wrinkling process is triggered by the autonomic nervous system. More recently, the neurobiologist Mark Changizi has argued that the wrinkles are an adaptation that helped our barefoot (and barehanded) ancestors negotiate their environment during extended rainy periods; on wet surfaces, hands and feet, like tires, grip better when they’re ridged.
From The Best Facts I Learned from Books in 2015 by Kathryn Schulz: Why do your fingers and toes turn all pruney after soaking in water? I’d assumed that the answer was osmosis, until I came across the real explanation in Cynthia Barnett’s “Rain.” Since the nineteen-thirties, Barnett writes, researchers have known that people with nerve damage in their arms don’t develop water wrinkles in their fingers; subsequent scientists discovered that the wrinkling process is triggered by the autonomic nervous system. More recently, the neurobiologist Mark Changizi has argued that the wrinkles are an adaptation that helped our barefoot (and barehanded) ancestors negotiate their environment during extended rainy periods; on wet surfaces, hands and feet, like tires, grip better when they’re ridged.