Why do snakes flick their tongues?

Written by

Manjishtha Bhattacharyya

Fact-checked by

Britannica Editors

Last updated

Nov. 6, 2026 •History

When William Shakespeare warned of the venomous touch of a serpent’s forked tongue, he was quite off the mark. It would take almost two more centuries before a more plausible explanation of why snakes flick their tongues was proposed. The 18th-century French naturalist Jean-Baptiste Lamarck suggested that the forked tongue of snakes aids in sensory perception, helping them feel objects in their surroundings. Although his theory came remarkably close to the truth, there are nuances to this distinctly reptilian behavior that were beyond the reach of science at the time.

Modern science tells us that snakes flick their tongues to gather chemical information from their environments. When a snake flicks its tongue, it captures scent particles from the air or the ground and then retracts its tongue, along with these particles, into its mouth. The tongue then deposits these odor molecules on paired pads on the mouth’s floor. These pads transfer the scent particles to the Jacobson’s organ, also called the vomeronasal organ—a specialized chemoreceptor on the roof of the mouth that helps detect smells. The scent particles bind to and stimulate receptor molecules in the organ. This generates sensory messages that are transmitted to the snake’s brain. The vomeronasal organ is adept at detecting airborne and non-airborne odors, allowing the snake to analyze the chemical composition of its surroundings. To sum up, a snake flicks its tongue to “smell” its surroundings.

Snakes rely heavily on their sense of smell to find food, and the Jacobson’s organ plays a pivotal role. By flicking their tongues, snakes can detect the scent trails left by potential prey, such as rodents or birds, and accurately track and capture them even in the dark or in complex environments. Beyond hunting, tongue flicking also helps increase snakes’ awareness of their environment. It allows them to detect predators or other threats and find mates.

But why do snakes have forked tongues? Videographic studies have shown that each tip of a forked tongue samples odor molecules from different points in the surrounding environment—for example, from various locations on the ground over which the snake is moving. In addition, tongue flicking creates two pairs of air swirls that concentrate airborne odor molecules from each side onto the corresponding tip of the tongue. The molecules sampled from these two points are then delivered separately to the vomeronasal organ on the corresponding side of the snake’s mouth, providing distinct chemical information about its environment. This gives snakes a directional, or “stereo,” sense of smell—much like human vision, in which our two eyes provide two separate images of the same object from slightly different angles.

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