Everyone is familiar with wrinkling of the fingertips after prolonged exposure to water. While the exact mechanisms are not known, both an intact sympathetic nervous system and osmotic effects are important. Two recent articles cast a new light onto wrinkling. In 2011, Changizi et al1 speculated that wrinkled fingers are water-induced rain treads allowing maximal drainage of water from digits and improving grip under wet conditions. While Haseleu et al2 now have shown that water-induced wrinkling does not improve either touch acuity or dexterity in handling wet objects under laboratory conditions, it is still intriguing to speculate that perhaps wrinkling is an evolutionary advantage to increase dexterity, be it climbing wet trees or grasping fish out of a stream.
Burgdorf WHC, Hoenig LJ. A New Wrinkle. JAMA Dermatol. 2015;151(1):14. doi:10.1001/jamadermatol.2014.486