When you were first born, your skin was too big for your tiny body. It took six months before your skin really “fit.” Then, your skin became stretchable, like a rubber band.
When you grow much older, the muscles in your skin will become weak, and your skin will lose some of its stretch. It will be too big for you again, and little folds, called wrinkles, will develop.
Staying in the sun too much can also cause wrinkles. The sun dries out the oils in your skin, the oils that keep your skin from becoming dry.
People on diets sometimes find their skin wrinkling after they have lost a great deal of weight. The fat cells beneath the surface have been absorbed into the body to be thrown off as wastes. The skin, itself, eventually does shrink to fit the body, but at a slower rate.
If the skin of an adult were peeled off and spread out flat, it would cover 18 square feet, or about the size of a twin bed!