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SALT LAKE CITY — Pruny fingers and toes may serve as grip in wet conditions.
According to a study published in Biology Letters, skin on the fingertips and toes may wrinkle in order to handle submerged or wet objects.
Co-author Tom Smulders of Newcastle University and his colleagues found that submerged and wet objects were handled more quickly and efficiently with wrinkled fingers than unwrinkled. The wrinkles in dry conditions, however, were not as effective as unwrinkled fingers. They suggested that and the increased likelihood of damage as the reasons that fingers and toes do not stay wrinkled when dry.
Wrinkling occurs in the glabrous — or hairless — skin on human fingers and toes in response to water immersion due to the "reduction in the volume of the fingertip pulp, caused by vasoconstriction, which in turn is controlled by the autonomic nervous system," they wrote.
This pruny state may have helped human ancestors gather food and get stable footing in wet conditions or environments.
The wrinkles themselves may serve this purpose in at least two ways, researchers wrote:
- Give water an evacuation channel through the hills and valleys of the wrinkle between finger pad and object.
- Change the skin properties to be give them more flexibility, adhesion or an increase in friction.
The researchers recommended making a comparison of other species that share this feature in future studies to provide deeper insights into the time period in which this feature evolved and its primary function.
