What organ in snakes detects scent particles brought in by the tongue?

Jacobson’s organ, also called the vomeronasal organ, detects scent particles that snakes collect with their tongues.

A snake’s forked tongue does not smell in the same way a human nose does. As the tongue flicks through the air or along a surface, it gathers chemical particles. When the tongue returns to the mouth, its two tips deliver those particles to paired openings connected to Jacobson’s organs in the roof of the mouth. The brain can then interpret the chemical information, including clues about prey, predators, and potential mates.

The forked shape gives snakes a form of chemical direction-finding. If one tongue tip encounters a stronger concentration than the other, the difference can help the snake follow a scent trail. This is especially useful because many snakes hunt in dim light or underground, where vision is limited.

Jacobson’s organ is not the same as a lateral line, which is a sensory system found mainly in fish and some aquatic amphibians. A pineal eye is associated with light and biological rhythms, while pit organs detect infrared radiation in certain snakes. Snakes therefore combine several sensory systems, but tongue-borne scent particles are specifically routed to the vomeronasal organ.