When a cat encounters an interesting smell, such as human feet, it may exhibit a peculiar open-mouthed expression, often with a slight curl of the upper lip. This behavior is a normal and sophisticated part of feline sensory processing. Far from indicating disgust, this response allows cats to gather detailed information, highlighting how they perceive their environment beyond regular sniffing.
The Flehmen Response
The open-mouthed expression observed in cats after smelling something intriguing is a specialized action known as the Flehmen response. This response helps cats analyze odors by drawing air into a unique sensory organ. During this process, a cat holds its mouth slightly open, sometimes appearing to grimace or “sneer,” and may curl back its upper lip. This action facilitates a thorough investigation of the scent.
The key to the Flehmen response lies with the vomeronasal organ, also called Jacobson’s organ, an accessory olfactory organ located in the roof of the cat’s mouth. This organ is situated just behind the incisor teeth and connects to the nasal cavity via small ducts. When a cat performs the Flehmen response, scent molecules, often solubilized in saliva, are transferred through these ducts to the vomeronasal organ. This pathway enables the cat to process chemical signals that regular nasal sniffing might miss, effectively providing a combined sense of taste and smell.
Decoding Complex Scents
Cats engage in the Flehmen response for complex scents because these odors often contain non-volatile chemical compounds, such as pheromones, not easily detected through typical inhalation. Human feet, for instance, emit a concentrated blend of sweat, bacteria, and unique human pheromones. This chemical signature provides information to a cat. The Flehmen response allows the cat to “sample” and analyze these heavier molecules.
Pheromones are chemical signals that convey specific messages between individuals, providing details about identity, reproductive status, emotional state, or territorial boundaries. By using the vomeronasal organ to interpret these compounds, cats gain insights into their environment and the individuals within it. This chemosensory analysis allows cats to understand complex social and environmental cues.
Normal Behavior and What It Means
The open-mouthed behavior is normal and indicates a cat is interested in a particular scent. It is not a sign of disgust, despite how it might appear to human observers. Instead, this action demonstrates a cat’s commitment to investigating an odor and extracting all available information.
Besides human feet, other strong scents can trigger this response, including the urine or anal gland secretions of other cats, or unfamiliar objects in their territory. The Flehmen response underscores the sensory capabilities of felines and their reliance on smell to comprehend their surroundings. It serves as a testament to their ability to interpret the chemical language of the world.