Scientists have a reason for why the skin of your fingers and hands wrinkles when exposed to water for a long time. Toes could even wrinkle after a long walk on damp grass and not just through soaking your feet. According to Neuroscientist Mark A. Changuzi, this pruning is not an unnecessary mechanism but an evolutionary advantage.
Structure of the skin
To understand the process of wrinkling, it is essential to know the structure of the skin. The skin has three primary layers. Its first layer is the epidermis, followed by the dermis and then the subcutaneous layer. The epidermis is divided into four layers; stratum corneum, the granular layer, squamous cell layer and basal cell layer. Wrinkling occurs at the stratum corneum.
The stratum corneum is sponge-like with dead keratin cells. When soaked, these keratin cells absorb water and swell. As it is soaked for a prolonged period, it becomes softer and more pliable to make up for increased fluid.
Although this wrinkling can occur anywhere, it is most notable on the skin of your toes, fingers, palms and soles of your feet. This is because the stratum corneum is thicker in these areas.
Why pruning occurs
Scientists have come up with several theories for this phenomenon. Initially, scientists believed that wrinkling reduced sensitivity and, therefore, damage to the skin.
Changuzi has studied how hands work, and that also includes pruning. According to him, pruning is not just a physical reaction.
Changuzi gives two reasons for pruning. The first is that the wrinkles provide channels for draining the excess water. Another reason for the wrinkles is to prevent slipping. Wrinkled skin on your feet or hands has a skid-proof characteristic that keeps you from slipping when you walk on a wet surface.
In a recent study, scientists asked participants to soak their hands for 30 minutes. The scientists then told them to pick up wet marbles. They compared the time they used to pick marbles against the time used by people with dry and normal hands. Results showed that the participants with wrinkly hands had an easier time picking them up because they had a better grip.
