Have you ever ever spotted your cat pull a face as though they’ve simply smelt essentially the most disgusting factor ever? Eyes closed, mouth huge open, lip curled in, neck prolonged—it’s an expression that indisputably resembles repulsion. That is in truth a herbal reflex referred to as the Flehmen reaction (every now and then known as the Flehmen grimace or response too). And, apparently, it has not anything to do with detecting a nasty odor.
Slightly, this can be a methodology that cats (and a few different species) have advanced with a purpose to procedure sure pheromones. So, what’s it, and why do cats do it? First, we wish to perceive the aforementioned pheromones.

Cat Conversation and the Function of Pheromones
Pheromones are messenger molecules that cats use to keep in touch with every different. They’re chemical compounds which are secreted outdoor of the frame in fluids like urine and sweat. Necessarily, pheromones are a hidden type of verbal exchange. Positive species use them as indicators from one particular person to some other.
Examples of ways in which cats use pheromones come with:
- Rubbing their cheeks onto issues
- Urinating on items and surfaces to “mark their territory”
- Emptying the contents in their anal glands when they’re wired or worried (those are two odor glands on each side of the anus)
- Butting their head towards somebody, which identifies her or him as “secure”
What Is the Flehmen Reaction in Cats?
The Flehmen reaction is an ordinary behavioral reaction that cats “carry out” once they stumble on sure pheromones. In daily lifestyles, cats are repeatedly responding to stimuli; those stimuli will also be odors, pheromones, sounds, tastes, and extra. By means of the usage of the Flehmen reaction, cats are in a position to procedure smells and pheromones, after which get entry to the tips it may well be telling them.
The purpose of the Flehmen reaction is to convey the air retaining the odor or scent over one thing known as the vomeronasal organ (additionally known as the Jacobson’s organ). When cats carry out the Flehmen reaction, two small ducts at the back of the incisor tooth of the highest jaw open up. The hole of those ducts lets in the odor or pheromone to trip to the vomeronasal organ.
This organ is a small little bump at the roof of the mouth that processes pheromones and hormones—no longer simply the ones of alternative cats, but additionally possible predator and prey species. It perceives the odor as one thing greater than only a odor, however not up to a vibration.
From right here, the indicators trip to the odor middle of the mind, after which to the hypothalamus. This can be a essential and busy a part of the mind that may affect reproductive hormones and behaviour.
We’ve damaged the pathway down into a number of steps, however in actual time the entire procedure happens in seconds, or much less. Your cat can then make a decision what to do with the received knowledge. They may run or they could do not anything; they could urinate or sleep; or they could pass searching for a possible mating spouse.
What Does the Flehmen Reaction Glance Like?
If you happen to haven’t stuck your cat in truth sporting out a Flehmen reaction, you’re most probably questioning what this outstanding and curious face-pulling in truth seems like.
Your cat will suppose a facial features as though they’ve smelt one thing very ugly. They normally hang their mouths huge open and curl their higher lip. This exposes the higher entrance tooth, referred to as the incisors. Whilst they do all of this, cats are inhaling to transmit the odor to that vomeronasal organ of their mouth.
In some cases, cats will stretch their neck out or hang their head at a humorous attitude to optimize the processing of the scents and odors. Your cat will simplest hang this pose for a minute or much less, ahead of resuming their standard expression and actions. If the messages aren’t tremendous transparent, they are going to carry out the Flehmen reaction a 2nd or 3rd time.
What Reasons the Flehmen Reaction in Cats?
It might appear logical that the Flehmen reaction is an involuntary or instinctive motion, however cats in truth need to make a decision to do it. The Flehmen reaction is a voluntary motion taken by way of cats when they’re uncovered to an enchanting scent or pheromone of some other animal (generally some other cat).
The Flehmen reaction is often utilized by male cats smelling feminine cats’ urine to evaluate if she is able to mate. On the other hand, it may be utilized by any cat once they come throughout a odor that they deem worthy of additional investigation.
Do I Wish to Be Anxious In regards to the Flehmen Reaction?
No—the Flehmen reaction is completely standard cat habits. In spite of its abnormal look, there’s not anything to fret about, and your cat isn’t in any discomfort or ache. Your cat will in most cases be completely calm.
The Flehmen reaction will have to be outstanding from cats which are respiring with their mouth open for a protracted time period. Those cats will in most cases be in misery and feature worked or fast respiring. Open-mouth respiring indisputably is regarding and warrants a seek advice from to the veterinarian.

Conclusion
Many different animals showcase the Flehmen reaction, together with horses, giraffes, lions, tigers, and extra. Some folks could have a vomeronasal organ, however they aren’t practical in folks; in different phrases, they’re a remnant of evolution that we don’t use.
We are hoping this text has helped you already know this distinctive habits out of your tom cat!
Featured Symbol Credit score: Bea Llonador, Shutterstock