Why doesn't the skin on your stomach wrinkle after a swim?

The skin on your stomach doesn't wrinkle after a swim because it has a different composition and thickness compared to other areas, like your fingers and toes. When submerged in water, the skin absorbs moisture, causing temporary wrinkling primarily in areas with thinner skin and more nerve endings. This response may help improve grip in wet conditions. Additionally, the skin on your stomach may not be exposed to the same pressure and friction as parts of your hands and feet, which can also influence wrinkling.