Why do cats make a stinky face

You may occasionally notice your cat making a strange face – a lip-curling grimace with the mouth half open, a wrinkled nose, and a raised chin. The look is usually accompanied by a hypnotic stare, appearing as if the cat is mesmerized. This response is known as Flehmen. You may find it somewhat disconcerting, but fear not, your cat only makes this face when he wants to get a better smell of something in the air, usually the pheromonal odor of another cat.

Pheromones are substances produced by animals that act as a form of chemical communication. In cats, different glands secrete different pheromones that affect a number of behaviors. For example, pheromones help in the attraction of a mate and provide information about a cat's reproductive status. They also are used to mark objects and territory and some promote a sense of well being or familiarity. Pheromones are akin to fingerprints in humans, and their deposition serves as a calling card of sorts.

When your cat exhibits the Flehmen response, it is to open the vomeronasal organ, or Jacobson's organ, a tiny cigar-shaped organ located in the roof of the mouth. This organ is thought to supplement the olfactory system and is especially concerned with the detection of pheromones. Larger cats, such as lions and cougars, a few mammals (including horses), a few bats, and all snakes have the vomeronasal organ and employ the same Flehmen response.

Both male and female cats employ the response in areas where other cats have marked the territory by spraying. It is thought that Flehmen provides information about the identify of the cat that left the scent, whether or not it is a stranger, and what is its sex and reproductive status. By Flehmen, males can determine whether a female is in estrus and therefore ready to mate.

Your cat evolved as a hunter with many keen senses But of all the senses, his sense of smell is superior; especially up close, and it is one of the ways he navigates around his environment. So when your kitty makes his funny face, keep in mind that he is merely exhibiting another marvelous part of his genetic make-up handed down from his erstwhile feline ancestors. And that's nothing to sniff about.

Have you ever observed your cat with his mouth partially open and upper lip pulled back in what appears to be a sneer or a look of disgust? Typically this will be accompanied by a look of intense concentration. This behavior is called the “Flehmen response” and can also be seen in other animals.

Your cat has something called a Jacobson’s organ, or vomeronasal organ, located in the roof of the mouth behind the front teeth. When your cat makes this strange face, it is because he has smelled something interesting and is drawing the scent into the Jacobson’s organ to get a better smell. The tongue traps the scent and transfers it to the vomeronasal organ in the roof of the mouth for better analysis.

Along with your cat’s highly-attuned sense of smell, the Jacobson’s organ provides additional sensory information and is especially attuned to detecting cat pheromones. So while it might look like your cat is disgusted when exhibiting the Flehmen response, your cat is actually enjoying a particularly interesting scent.

Have you ever seen your cat exhibiting the Flehmen response?

Written by Newby on 23 January 2018.

Dear Pet Column

My cat makes often makes this weird face when she is sniffing an object and looks up with her lips curled and slightly back, a look of utter disgust / confusion / concern that makes me laugh heartily. I call it “cat stinky face” and my friends say their cats do it too. Why do cats do this and should I be concerned?

So “cat stinky face” is a real thing with a real scientific name, flehmen. As a cat myself I can assure you there is nothing alarming about this gesture. Although it looks comical it's actually highly purposeful and interesting.

Yes, the flehmen response looks like a cat frozen with its mouth open, with their lips rolled back over the teeth to resemble a sneer. Although we cats can have strong opinions and will communicate them to you, this cat stinky face isn’t necessarily a snooty reaction but a type of sniffing. It is unique in that, while “flehmening”, instead of using our nostrils we are inhaling the air through our open mouths.

Anthrozoologist John Bradshaw shared with Slate magazine that the flehmen response opens up two small ducts, also known as the nasopalatine canals, on the roof of an animal’s mouth behind the incisors. These ducts then go through the roof of the mouth and join up with the vomeronasal organ which functions as an auxiliary olfactory bulb of sorts.

Bradshaw shared that some scientists believe the flehmen response does something that’s between the sense of smell and taste (I knew it - we DO have a sixth sense!). So the flehmen isn’t an automatic way to take in smells, as one does through involuntarily breathing, but it is more of a voluntary and controlled process – serving a specific purpose.

So what is the purpose of cat stinky face (so much for fun to say than “flehmen”)? It is believed that we do this to detect chemical stimuli, such as pheromones, that are present in urine and feces, or areas that cats have marked with scent glands,Male cats usually flehmen more than female cats as it is mostly used in relation to mating and using scents to determine compatibility and if timing is right (wink wink).

A few more fun flehmen facts:

It is not restricted to cats. Along with domestic cats, large cats such as lions and tigers, also make the face as do horses, giraffes, buffalos, goats and llamas.

Cats actually have better vomeronasal organs than dogs. An average house cat has 30 different receptors in that organ, whereas a hound dog has a measly nine. (I knew we were more talented than dogs!)

Humans used to have the vomeronasal organs necessary for a flehmen response — but they got phased out in the evolutionary process (what - did compatibility and timing no longer matter?)

So, keep enjoying those cat stinky faces and take some photos and send them in to Second Chace to share the good laughs!

My name is Newby, although sadly I am no longer new to the shelter, or even the Pet Column for that matter. I have been waiting and waiting for my new home. Not sure why it is taking so long. I am handsome, only 5 years young and have a fabulous attitude and love people. I do enjoy funny faces and promise to bring many smiles to your face if you adopt me.

My incredibly curious cat Merritt (she’s a busy-body calico) is sniffing something again, which isn’t surprising. What is surprising is when she sniffs an object and looks up with her lips curled just slightly back. At first, I thought it was simply a look of concern or surprise over what she had just smelled. But that “cat stinky face” has a scientific name, flehmen, and cats aren’t the only ones who do it. So, what is a cat flehmen response and why does it happen? Let’s take a look. 

What does a cat flehmen response look like?

I’d best describe the cat flehmen response as a look of utter, lip-curling disgust / confusion / concern that elicits some true laugh-out-loud reactions from the cat parents that catch their kitties doing it (see Merritt’s face above during her — supervised and ribbon-less! — prance in our discarded holiday gift wrap). “The flehmen response looks like a cat frozen with her mouth open,” Dr. Sasha Gibbons of Just Cats Veterinary Hospital in Stamford, Connecticut, explains. “Sometimes, cats will roll their lips back over the teeth as well, which can resemble a sneer.”

What is a cat flehmen response?

My cats have some strong opinions and “pooh pooh” at everything from house guests to new toys. But, the cat stinky face isn’t necessarily a snooty sneer — it’s actually way more scientific than that. “The flehmen response is a type of sniffing, but instead of using their nostrils, cats inhale the air through their open mouths,” Dr. Gibbons says.

Anthrozoologist John Bradshaw tells Slate that the flehmen response opens up two small ducts, also known as the nasopalatine canals, on the roof of an animal’s mouth behind the incisors. Those ducts then go through the roof of the mouth and join up with the vomeronasal organ (a.k.a. the Jacobson’s organ), which according to Bradshaw, functions as an auxiliary olfactory bulb of sorts.

Slate also reports that some scientists believe the flehmen response does something that’s between the sense of smell and taste (so cats, sort of DO have a sixth sense!). The ducts contain saliva, meaning that whatever goes in must be voluntarily brought up to the vomeronasal organ. In other words, flehmen isn’t an automatic way to take in smells, as one does through breathing.

The article goes on to explain that cats actually have better vomeronasal organs than dogs. An average house cat has 30 different receptors in that organ, whereas a hound dog has a measly nine.

Why does a cat flehmen response happen?

“Cats use the flehmen response to detect chemical stimuli, such as pheromones, that are present in urine and feces, or areas that cats have marked with scent glands,” Dr. Gibbons says.

But here’s an interesting fact — male cats usually flehmen more than female cats! “Male cats use the flehmen response in relation to mating,” Dr. Gibbons explains. “Scents can help indicate compatibility and if timing is right.”

Of course, there are exceptions to the cat flehmen response, as with my cats. I catch Merritt, my female kitty, displaying a flehmen response to something about once a day. I’ve only seen my male cat, Gabby, flehmen a handful of times in the five years we’ve had him.

Are cats the only ones who display a flehmen response?

Nope! “Along with domestic cats, large cats such as lions and tigers, also use the flehmen response,” Dr. Gibbons tells us. “Outside of the cat family, horses, giraffes, buffalos, goats and llamas have also been seen demonstrating the flehmen response.” Slate reports that humans used to have the vomeronasal organs necessary for a flehmen response — but they got phased out in the evolutionary process. Bummer!

Should you ever be concerned about a cat flehmen response?

Thankfully, the answer is a definite no. “As funny as it may look, there is no harm to a cat exhibiting a flehmen response,” Dr. Gibbons advises. So, enjoy those cat stinky faces (and take some photos — there are not enough good #flehmen pics featuring cats on Instagram!). A cat flehmen response is normal and you have nothing to worry about!

Tell us: Have you ever witnessed a cat flehmen response? Do you have any nicknames for it? What do you think it looks like?

Thumbnail: Photography by fotostok_pdv/Thinkstock. 

This piece was originally published in 2018. 

About the author

Cait Rohan Kelly is a digital writer, editor and marketer with over a decade of experience working with everything from sports stars to different types of cheese. She is currently the Digital Content Marketing Manager for Catster and Dogster. Cait is a lifelong animal lover and cat lady. She lives in Connecticut with her husband (a self-professed cat dude), her son (his first word will probably be one of her cats’ names) and her two rescue cats — Gabby, an orange tabby and avid sleeper, and Merritt, a sassy calico.

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