Snakes use their tongues to smell.
Have you ever thought about why snakes put out their tongues? They're probably trying to smell their surroundings with their tongue. They have a Jacobson's or vomeronasal organ on the roof of their mouth. The odor then travels from the tongue to an organ in their mouth. Their odor is particularly pleasant and has been characterized as smelling in stereo. They have a long tongue and numerous sensors that can detect varying levels of chemical stimuli.