Rat snakes typically begin the shedding process in early spring, as the weather begins to warm up and they begin to emerge from their winter hibernation. As the days grow longer and their bodies become more active, they start to actively shed their old skin, which starts to flake off in patches until it has been completely replaced.

Rat snakes shed because their bodies are covered in scales made of keratin, the same protein that makes up hair and fingernails in humans. This keratin is continually produced, which pushes up the older, outermost layer of scales. This causes the skin to separate and die off. Shedding frequency depends on the age and size of the rat snake.

The shedding process initiates when the snake’s body becomes too large for the old skin to contain it anymore. So, the old skin will begin to dry out and separate from the newly-formed skin layer underneath. At that point, the shedding process will begin, during which the snake will remove the old layer and either discard or eat it.