Snakes almost always have their eyes closed. While that would cause a big problem for humans, for snakes it is no real issue. Humans have thick eyelids. When our eyelids are closed, basically no light gets through them and we cannot see. For snakes, that same problem does not exist. A snake’s eyelids are very thin and transparent, allowing the snake to look out into the world when his eyelids are closed. Because of this, snakes almost always have their eyelids closed as eyelids are a natural protector of the eyes.