Why does a snake's tongue flash out ?

When a snake crawls, its tongue flicks in and out. This action is very useful to the snake.

The tongue of the snake is a very important sense organ. The snake has no fingers and toes with which to feel. The tongue has a sense of touch and takes the place of fingers and toes. The snake can smell with its nose but the tongue helps the nose as it too has the sense of smell.

The sense of touch and smell in the tongue helps the snake to find its food. It also helps the snake to search for another snake in the mating season.