Pruney is Prudent

The "Really?" section of the Science Times this week tackles an interesting claim: that fingers and toes wrinkle when exposed to water because of water absorption. That's conventional wisdom, anyway. 

There are a couple of questions, however. Why do only our hands and feet prune, and why is the wrinkling most extreme at the ends of toes and fingers? I didn't know this before, but cutting nerves in a finger prevents pruning, and pruning has been confirmed only humans and macaques.

The authors of a recent study in Brain, Behavior and Evolution report that the wrinkles consistently form a pattern of unconnected channels, allowing water to drain away when fingers are pressed to wet surfaces. This permits more contact and, theoretically, increases traction. The authors are planning a future study to examine if wrinkles do indeed create a better grip, and whether mammals in wet habitats show wrinkles more often.


Interesting possible ultimate cause of wet pruning. The more you know!