Why do we get pruney fingers?

Wrinkled fingers: a body response mechanism for gripping objects in wet conditions

Pruney fingers, also known as wrinkled skin, are a common occurrence after spending a long time in the water, such as taking a bath, surfing, swimming, or washing dishes.

Surfing in cold water is an adventure. And after a freezing experience in the icy waves, there's nothing better than a hot bath.

The problem is when that warm bath is too long. The result is pruney fingers. But why does it happen?

This phenomenon is caused by the activation of specific nerve cells in the skin called sensory neurons, which are responsible for detecting stimuli such as temperature, pressure, and touch.

When the skin on the fingers comes into contact with water, the sensory neurons in the skin send signals to the brain, causing the blood vessels in the skin to constrict or narrow.

This constriction of the blood vessels causes the skin on the fingers to wrinkle, similar to how a raisin becomes wrinkled when it is dried out.

A Better Grip

Three scientists from Newcastle University solved the mystery of the water-wrinkled fingertips. Apparently, it's all in genetics.

Kyriacos Kareklas, Daniel Nettle, and Tom V. Smulders discovered that wet objects are easier to handle with wrinkled fingers than with dry, smooth ones.

The wrinkled skin on the fingers is thought to be an adaptation that helps to improve grip on wet objects, such as when washing dishes or holding onto a wet bar of soap.

It is important to note that the wrinkling of the skin on the fingers is not caused by the absorption of water into the skin, as was previously thought.

Instead, it is the result of a complex interplay between the nervous system, blood vessels, and skin cells in response to the presence of water.

Genetic Evolution?

The researchers believe that this is a genetic evolution from our ancestors' time when they had to get food in wet conditions.

"If wrinkled fingers were just the result of the skin swelling as it took up water, it could still have a function, but it wouldn't need to," explains Tom Smulders from Newcastle's Centre for Behaviour and Evolution.

"Whereas, if the nervous system is actively controlling this behavior under some circumstances and not others, it seems less of a leap to assume there must be a function for it and that evolution has selected it."

"And evolution wouldn't have selected it unless it conferred some sort of advantage."

The hypothesis that water-induced finger wrinkles improve the handling of submerged objects and that it was a genetic adaptation to survival mode will continue to be studied.

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