Why do snakes have scaly skin?

Snake bodies are covered with plates and scales, which help them move over hot surfaces like tree bark, rocks, and desert sand. Rough belly scales help the snake keep its grip on rough branches and push off of surfaces when it needs to move. The scales are also waterproof, helping keep water away from the snake’s body. The scales are made up of many layers of cells. The outer cells are dead and protect the living ones underneath them. Several times each year a snake sheds a layer of its dead skin, allowing a new layer to emerge. Before the skin peels, the snake is sluggish, its colors become dull, and its eyes turn cloudy. When a snake is ready to shed its old skin it rubs up against a rough surface, like a rock, to rip its skin. Then it glides out. Snakes shed their skin so they can grow, as well as to remove parasites along with their old skin.