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Pruney digits help people get a grip

Wrinkling may have evolved as an adaptation to wet conditions

Scientists have an answer to the pressing question of why hands and feet get wrinkled after too much time in the bath: Pruniness may have evolved to make it easier to handle wet objects.

The smooth skin of human hands and feet becomes furrowed after extended periods in water. Though often assumed to be a result of water passively seeping into the skin, the phenomenon is actually caused by the nervous system constricting blood vessels. As early as the 1930s, surgeons noticed that no wrinkling occurred if a finger nerve had been severed, so furrowing has been used as a medical indicator of nerve function. But what evolutionary purpose wrinkling serves, if any, remained a mystery.

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