Why do cats make a weird face when they smell certain things?

Answered by Ricardo McCardle

The flehmen response, also known as the flehmen reaction or flehmen grimace, is a fascinating behavior observed in cats and various other animals including goats, tigers, and horses. It is commonly seen when these animals encounter interesting smells, particularly pheromones, which are chemical compounds secreted by animals to communicate with others of their species.

When a cat comes across a scent that piques its interest, it may exhibit the flehmen response as a way to process and analyze the smell more effectively. This behavior involves a distinctive facial expression that may appear strange or weird to us humans. The cat will tilt its head slightly back, open its mouth, and curl back its upper lip, exposing its front teeth. This action creates a sort of grimace-like expression, which is where the term “flehmen grimace” originates.

The purpose of the flehmen response is to transfer the scent molecules from the air into a special organ located in the roof of the cat’s mouth called the vomeronasal organ, or Jacobson’s organ. This organ is specifically designed to detect pheromones and other chemical signals. By curling back its lip and exposing the front teeth, the cat creates a pathway for the scent molecules to enter the vomeronasal organ.

The vomeronasal organ plays a crucial role in a cat’s communication and reproductive behaviors. It helps the cat gather information about potential mates, identify territorial boundaries, and even detect the scent of prey. The flehmen response allows the cat to intensify its perception of the scent, as the pheromones are directly detected by the specialized receptors in the vomeronasal organ.

So why does the cat make a weird face during the flehmen response? The curled lip and exposed teeth are not indicative of aggression or discomfort but rather serve a functional purpose. By creating a specific facial expression, the cat is able to direct the scent molecules toward the vomeronasal organ more efficiently. It’s important to note that the flehmen response is a natural and instinctive behavior in cats, and it is not limited to specific smells or situations.

In my personal experience with cats, I have witnessed this peculiar facial expression during various instances. For example, when introducing a new cat into the household, resident cats may exhibit the flehmen response to familiarize themselves with the newcomer’s scent. Additionally, I have observed this behavior when my cats encounter unfamiliar objects or substances with intriguing smells. It is truly fascinating to witness how they use the flehmen response to further investigate and understand their environment.

Cats make a weird face, known as the flehmen response, when they smell certain things because it allows them to transfer scent molecules to their vomeronasal organ more effectively. This behavior helps them process pheromones and other chemical signals, aiding in their communication and reproductive behaviors. The flehmen response is a natural and instinctive behavior that is not limited to specific smells or situations, and it is intriguing to observe in our feline companions.