What sensory organ allows dogs to detect pheromones and chemical signals?

The story behind the answer

Jacobson’s organ (the vomeronasal organ) is the accessory olfactory system specialized for detecting pheromones and other non-volatile chemical signals. Located at the base of the nasal septum, it sends information to brain areas that regulate social and reproductive behaviors, helping dogs interpret messages about mating status, territory, and emotional state. You may notice dogs lick or “tongue-flick” after sniffing—behaviors that help move chemical cues toward this organ.

By contrast, the main olfactory epithelium senses general airborne odors, trigeminal receptors detect irritants and temperature (like ammonia or menthol), and nasal turbinates are bony structures that increase airflow surface area but aren’t sensory organs themselves. Memory tip: Vomeronasal = “V for Valentine”—the system for love and social signals.