Wrinkled fingers improve grip on wet objects: research

Research carried out by scientists from Newcastle University in England has confirmed that wet objects are easier to handle with wrinkled fingers than with dry, smooth ones.

The results, which are reported in the Royal Society journal Biology Letters, suggest that the creases which form on our fingers and toes when we stay in water too long are because humans evolved in this way to improve handling objects in wet conditions.

Experts previously assumed that the wrinkles were caused by the skin swelling in water, but more recent research showed that creation of the ridges was a response controlled by the body's sympathetic nervous system.

This revelation led researchers to conclude that the wrinkling effect must have some function, so the UK scientists asked 20 volunteers to take part in a experiment where they manipulated submerged and dry objects both with wrinkled and unwrinkled fingers.

The volunteers had to pick up marbles and ball-bearings immersed in a bucket of water between the index finger and thumb of one hand before depositing them with their other hand in a second container.

The next test involved handling dry objects with both wrinkled and unwrinkled fingers.

The researchers found that while there was no advantage from ridged fingers when moving dry objects, the volunteers with wrinkled fingers regularly completed the task of moving wet objects faster than those with unwrinkled fingers.

Further research is necessary to discover how this phenomenon works although it could be that the ridges help the water flow more easily away from the fingertips, thus improving grip.

Scientists also wonder why our fingers are not permanently wrinkled as this would not affect our ability to handle dry objects.

One possible reason is because this could reduce sensitivity and, accordingly, increase susceptibility to injury.