Cats are equipped with a very special piece of equipment known as the Jacobson’s organ or vomeronasal organ. Located in the roof of the mouth, it contains ducts that lead to the mouth and to the nose. This is essentially a scent analyzer. It’s used primarily for analyzing pheromones (scent chemicals) from other cats, especially the ones found in urine.
How it Works
The scent is collected in the mouth where the cat then uses his tongue to flick it up to the vomeronasal organ. You can tell when the cat is in the process of using his vomeronasal organ because his facial expression is similar to a grimace. His upper lip will be curled and his mouth will be partially open. This expression is known as the flehmen reaction.
The Purpose of the Vomeronasal Organ
Although all cats have this organ and can use it whenever they come across any scent they feel requires more in-depth analysis, it’s often used by intact males reacting to the pheromones in the urine of females in heat.