February 23, 2018

CT Naturalist: Why do Snakes Have Forked Tongues?

One of Connecticut’s most common and non-venomous snakes is the garter snake. Although familiar and often taken for granted, this snake can help us learn the truth behind a snake’s notorious forked tongue! (See video below):

The statement that snakes “smell with their tongues” is often uttered without enough explanation. This generic phrase is somewhat misleading as it gives the impression that a snake’s tongue acts alone in the smelling process.

Snakes have an olfactory (scent) sensor called the vomeronasal, or Jacobson’s organ.  This organ is located inside the nasal cavity above the roof of the mouth. Each time a snake whips out its tongue, it captures chemicals from the air or water and carries them back into its mouth. The tongue then rubs against the vomeronasal organ where the scent is processed. So the tongue does not do the smelling; rather, it aids in the smelling process.

Here’s where it gets even more interesting.

On the roof of the mouth are two holes where each tip of a snake’s forked tongue touches the vomeronasal organ. A snake is able to comprehend which direction a scent is coming from based on which tine of its tongue (left or right) has captured a stronger scent.

Directional smelling is an advantage when a snake is hunting prey or avoiding predators. A key function of the vomeronasal organ is detecting pheromones, helpful when searching for a mate.