How do lizards smell with their tongues?

Lizards do not "smell" with their tongues in the same way humans smell with a nose; rather, they use their tongues to collect chemical information from their environment to be processed by a specialized sensory structure called the Jacobson’s organ (or vomeronasal organ).12

The process functions as follows:

• Collection: As a lizard flicks its tongue in and out, the tongue picks up airborne odor molecules or chemical particles from the substrate.23
• Transfer: Upon retracting the tongue into the mouth, the lizard touches the tongue tips to openings located on the roof of the buccal cavity.14
• Identification: The chemical particles are transferred to the Jacobson’s organ, which identifies the molecules and sends sensory messages to the brain.12

This system, often called vomerolfaction, allows lizards to track prey, identify potential mates, and detect territorial markers. While some lizards rely primarily on vision, autarchoglossan lizards—such as skinks and monitor lizards—rely heavily on this chemosensory process to navigate their surroundings.564