Why do snakes stick out their tongues?

The forked tongue of a snake may look dangerous, but it is perfectly harmless. Each and every time the snake flicks out its forked tongue, it snares chemical particles in the air, which latch onto, or dissolve in, the moisture of the snake’s tongue. Once the snake reels in its tongue, it inserts the tips of the forked tongue into the two openings of a special organ called the Jacobson’s organ. The particles, especially those of animal body odours, are identified and analyzed by the Jacobson’s organ. Once the snake has identified the animal, person, or object, it slithers into action. The deep fork in the tongue serves a very useful purpose- it allows the snake to sample a wider area than an undivided tongue.