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Sometimes, understanding our cats can seem as easy as reading a book.

A demanding meow by the door sends a clear signal that it’s time to open up. Pushing their head into our hands lets us know that they need to be pet.

But sometimes, cats do things that just don’t make sense. At least, not to us humans. Unusual, weird, and strange mouth movements are some of the most confusing and sometimes even concerning cat behaviors.

Whether it’s a weird chewing motion without actually having anything in their mouth or the open-mouthed stink face, there’s a wide range of strange feline mouth movements.

What’s going on here and why do cats make weird mouth movements?

In most cases, you’re probably seeing one of two things: either chattering or the fleming response. Both of which are completely normal but cause cats to make strange mouth movements or put their mouth in particularly weird positions. In other cases, weird mouth movements could be related to a health issue. 

Let’s take a closer look at each possible explanation starting with the most likely answer.

Reason 1: It’s A Cat Chatter

The cat chatter is one of the absolute weirdest things that cats can do. It looks like a rapid chewing motion but you won’t find anything inside your cat’s mouth. Cats will also make a high-pitched, almost chirping-like sound when they do it.

When cats chatter, they’re usually extremely focused on some kind of prey. That’s because the kitty cat chatter is thought to be a combination of excitement, frustration, and anticipation all directed towards potential prey that’s usually just out of reach.

But it’s much easier to show you what this looks like instead of only using words so check out this video and compare it to what you’re seeing:

Cat chattering is far from uncommon but it’s also not something your cat is going to do every day which just adds to the mysteriousness of this behavior. As if that wasn’t enough, scientists aren’t even entirely sure why cats do the chatter.

There are some solid theories out there, many of which make a lot of sense, but they’re still just theories.

The most common explanation is that the chatter is a sort of frustration or excitement response when cats see prey outside the window. The idea here is that cats are excited to reach their potential prey but also very frustrated that they can’t.

Others have suggested that cats are actually chattering in order to mimic the sound of the birds they’re trying to catch. While that sounds like a bit of a stretch to me, scientists have discovered that a wild cat in the Amazon rainforest does exactly that.

Then there are the videos like this one that shows cats chattering seemingly to each other. Sure, there’s a window there with potential prey but if you watch that entire video it certainly does appear that those feline friends are having a chattering conversation.

If your cat is chattering when they spend time at the window or when you play with a wand toy, then the weird mouth movement is likely related to the cat chatter. Whatever the exact reason for the response, you can rest easy knowing that the chattering behavior is completely normal for cats. 

Reason 2: It Could Be The Famous Flehming Response

The Fleming response is one of the funniest, silliest, and weirdest movements a cat could make with their mouth. This response goes by many names including the infamous feline stink face!

Cats will roll up their lips and keep their mouth ajar for several seconds. They sometimes squint their eyes as well which creates an overall look of shock or even disgust. Again, it’s easier to see it than describe it with words and you can check out this handsome feline showing off the Flehmen response in this video:

What’s going on here?

First of all, this weird movement doesn’t mean your cat is disgusted! Instead, they’ve just found a smell that’s particularly interesting to them and the Flehmen response allows them to get the full experience!

Cats have something called the Jacobson’s organ which allows them and many other animals to more deeply smell a particular scent. Snakes are most famous for this organ and it allows them to constantly track down prey but it’s found in several mammals including big cats and horses.

Because the Jacobson’s organ is located far back in the mouth, cats need to take on this special mouth movement, called the Flehmen response, in order to really get the scent.

Part of what makes this mouth movement so strange is that we rarely see our cats with an open mouth. While cats can pant, it’s not common and we usually associate panting with dogs. That makes it even more surprising when we see a cat with their mouth hanging open!

Different cats will show the Flehmen response more or less frequently but it’s almost always preceded by heavy smelling. Essentially cats start sniffing something and decide they need to get a better idea of what they’re smelling. That’s when they break out the Flehmen response to take things up a level!

You’re more likely to see this with unusual, stinky smells and even more so if it’s a scent from another animal or cat. Felines will use the Flehmen response to get as much exposure as possible if they encounter pheromones or something usual.

For whatever reason, my cat Debbie does this any time I present her with my electric toothbrush. I’m not sure what that says about my oral health and the cleanliness of my toothbrush but she will do it every single time.

There’s really nothing to worry about when it comes to the Flehmen response and it’s a completely normal part of being a cat. You can try to trigger this response by safely presenting your cat with interesting smells around the house. You don’t want to expose your cat to anything harmful but letting them sniff a few household items (like your toothbrush) will give them some mental stimulation and likely keep you entertained as well!

Reason 3: Is Your Cat Panting?

Your cat’s weird mouth movement could be related to panting.

We’re used to seeing panting in dogs but when our cats do it, it can be a little more surprising. Panting can be normal, in very specific scenarios, but it can also be related to a long list of medical concerns including overheating.

Even though most people have seen a panting dog before, you probably haven’t seen a panting cat and so the mouth movement may look a little strange. Cats are much more subtle when they pant and don’t make nearly the same amount of noise that many dogs do.

Like dogs, it can be normal for some cats to pant after vigorous exercise as a way to catch their breath. You can check out this handsome orange cat taking a breather after chasing down his favorite toy for an example of this:


Just to be clear, that doesn’t mean you should ignore panting even if it’s directly connected to exercise. It could still be a symptom of several concerning conditions including asthma or heart failure.

If you think the weird mouth movement you’re seeing is panting, talk to your veterinarian and if possible take a quick video so your veterinarian can see exactly what your cat is doing.

Reason 4: There Could Be Something In Your Cats Mouth Or Throat

hate having a piece of food stuck in my teeth. Luckily, I always carry some extra floss around so it’s not a problem. But if I forget my floss, you can certainly expect some weird mouth movements out of me as I try to get the food loose.

A little gross, I know.

Our cats don’t have the luxury of flossing! But they still may suffer from something stuck in their teeth from time to time. If this happens, you’ll not only see weird mouth movements but also some pawing at their mouth too. If something is stuck in their throat and mouth, you may even see some gagging or retching.

The most common culprits here are going to be hard kibble, a bone, part of a toy, a piece of their collar, or even their own hair in some cases. In other words, it could be quite a few things.

When it comes to kibble or hair, it will usually sort itself out and your cat will probably be able to successfully loosen it up with some up, down, and side to side motions of their mouth. Time is also on your side here as these items will usually break up on their own.

But with other items, your cat is more likely to need a little help.

You can start by taking a look inside your cat’s mouth. The video below is focused on administering an oral medication but it also gives you excellent instruction on how to look inside your cat’s mouth:

You may not have much time to look, but try to quickly spot anything unusual. Since you aren’t looking inside a cat’s mouth every day, figuring out what counts as unusual could be difficult but look for any inflammation of the tongue or gums and any redness.

You may not be to do anything about it at that moment but it will at least let you know know what you’re dealing with and help your veterinarian respond appropriately.

In some cases, the act of opening your cat’s mouth alone will help dislodge whatever is stuck.

If you notice that something is in your cat’s mouth and down their throat, do not try to pull it out. Objects like this are usually long pieces of string, also called a linear foreign body, and pulling them out of the stomach has the potential to cause a great deal of damage to your cat.

I’ve seen this several times with specific types of collars, especially elastic kinds that can fray. Cats will try to remove the collar with their mouth and in the process, they’ll accidentally swallow a portion of the frayed material.

Again, don’t try to pull this out if you see it’s down the throat. Instead, you’ll want to consult your veterinary immediately and let them know what you’ve seen.

In most cases, weird mouth movements related to something stuck in your cat’s teeth will be accompanied by pawing and if there’s an issue with the throat as well then cats may gag. You can open your cat’s mouth to get a better of what’s going on but don’t hesitate to consult your veterinarian.

Reason 5: Dental Disease

Dental disease is extremely common in cats and according to Cornell University, “Studies report that between 50 and 90% of cats older than four years of age suffer from some form of dental disease.”

Dental disease is a big catch-all term that includes a variety of minor and major conditions all of which can cause unusual mouth movements if they’re left untreated for too long.

But the folks at Cornell go on to explain that, “fortunately the most common forms of these diseases are largely preventable or treatable with appropriate preventive dental care and monitoring.”

That means not only visits to your veterinarian but also regular brushing at home.

So what does dental disease look like?

The overall severity is typically graded between one to four with category 4 being the most severe. You can see dental disease graded at each level in this image:

dental disease grading chart all four levels

Notice all the brown stuff on the teeth that gets worse with each grade?

That’s called tartar (also called calculus) and it’s the hardened form of plaque and bacteria. You’ll also notice that as more tartar is built up, the gums become more red, inflamed, and irritated. That inflammation is called gingivitis.

While some folks will often describe these are two different things, and they technically are, they still fall under the same big umbrella of dental disease. However, this is the kind of dental disease that is mostly preventable, or at least manageable, with regular brushing and trips to the veterinarian.

What isn’t preventable, are conditions like stomatitis that cause a severe inflammation to the gums, regardless of how clean the mouth is. Cats are also prone to a condition called tooth resorption that shows up as redness of the gums around a specific tooth, usually the premolars.

So not only is the jargon confusing, but so are the specific conditions! However, depending on the severity they can all cause cats to drool, refuse food or just make weird mouth movements.

But in most cases, you’d never know that cats have an uncomfortable mouth at all. Cats are absolute experts at hiding pain and even the most caring and attentive cat parent can miss the signs.

That means it will usually take quite a bit of pain for your cat before you notice any unusual mouth movements related to dental disease. In some cases, pain may increase after eating or chomping down on their favorite toys.

Some cats can even become aggressive as a result of the pain. If you’re seeing any amount of dental disease in your cat’s mouth, it’s a good idea to consult your veterinarian. Ideally, dental disease is addressed long before it causes pain or strange mouth movements.

Reason 6: Trauma

While dental disease is a condition that takes time to develop, a sudden wound or abrasion in the mouth caused by trauma could also cause weird mouth movements and could happen in an instant. Outdoor cats can be exposed to all kinds of accidents but trauma can also occur when it comes to indoor cats too.

Cats that like to chew could also cause a small cut in their mouth that can also lead to strange mouth movements.

What makes this difficult, is that many of the trauma-related reactions will look very similar to the discomfort you’d expect from dental disease. A cat with some kind of oral trauma may also paw at their mouth and have discomfort after eating. That can make it difficult to figure out what’s really going on.

You can refer to the video under reason 4 for a great explanation on how to check your cat’s mouth and look for any trauma. But as with any other condition, it’s always a good idea to consult your veterinarian.

Reason 7: Oral Tumors

An oral tumor could cause cats to do some strange things with their mouth, especially around mealtime. Not only is an oral tumor painful on its own, but it can also shift the structures in the mouth to cause increased discomfort.

Oral tumors aren’t going to be the most likely explanation for your cat’s behavior but they’re not uncommon either. According to the folks at Cornell University, “oral cavity cancer is the fourth most commonly diagnosed type of feline cancer. Surpassed in frequency of occurrence only by lymphoma, skin cancer, and mammary cancer, oral cavity cancer accounts for about 15 percent to 20 percent of feline malignancies”

The tricky part about oral tumors is that they’re much more difficult to spot early since most folks aren’t regularly looking deep inside their cat’s mouth. Of course, if you’re regularly brushing you’ve got a better chance of spotting these. Otherwise, you’ll notice symptoms like refusal to eat, drooling, and strange mouth movements before you spot the actual tumor.

Reason 8: Feline Orofacial Pain Syndrome

Feline Orofacial Pain Syndrome (FOPS) is an rare condition that causes mild to severe pain in a cat’s mouth. It’s usually focused on a particular side of the mouth and depending on the severity of the pain, it can cause cats to take on all kinds of strange mouth movements including exaggerated chewing and licking movements. Sadly, in many cases, it can lead to mutilation of the tongue, teeth, and other parts of the oral cavity.

While it is rare, I’ve never seen a case after 10 years in the veterinary field, it’s significantly more common in Burmese and related breeds.

For a better idea of what an episode of FOPS looks like, you can check out the video below. Just keep in mind that it’s sad to see this handsome orange feline so comfortable but know that his owner is taking great care of him.

What makes this challenging, is that the way this orange cat (his name is OJ) moves his mouth and lips is similar to any other uncomfortable oral condition. Because FOPS is related to a misfiring nerve, it’s also quite difficult to diagnose and is usually the very last thing you rule out after dental disease, trauma, or any of the other medical explanations on this list.

Reason 9: Did Your Cat Have A Dental Cleaning?

Dental cleanings are a regular and routine part of veterinary care for your feline friend. But they can often include more than just a cleaning and teeth that are too far gone will need to be extracted or removed.

This can change the position of other teeth and lead to some weird mouth movements as cats learn to adjust to the changes.

Of course, you don’t need me to tell you that after having teeth removed your cat’s mouth may feel strange.

But what isn’t so commonly discussed is what happens when one of the canines (those are the large pointy teeth) are removed.

While somewhat rare, I’ve seen several cases where the upper canine tooth is removed and as a result the lower canine suddenly starts sticking out and rests on the outside of the lip!

Some cats will eventually figure out how to keep these rogue teeth inside their mouth. But others will just let it hang out on the lip or will constantly try to shift the tooth by moving the lips around until it gets in the right spot.

That means cats could be showing strange movements long after their dental cleaning!

Your veterinarian can help you come up with a plan that works best for your cat and unless the stray tooth is causing damage to the upper lip it typically isn’t a problem.

Reason 10: Is It A Congenital Issue?

Just like humans, cats can have overbites and underbites that lead to odd confirmations of their teeth. These genetic conditions can make the mouth a little uncomfortable and lead cats to taking on some strange mouth movements.

This is probably the most unlikely reason but still worth a mention. Since it’s not something that will suddenly occur overnight, you don’t need to worry about this with an adult cat- at least most of the time.

But if your cat is still a kitten or is still growing then an unusual jaw shape could be at play. Again, this is quite rare but still a consideration.

Reason 11: Your Cat Could Be Congested

Feline upper respiratory infection is relatively unusual in cats that live in low-stress environments but unfortunately, it can be quite common in shelters. It’s commonly compared to a cold in humans and just like the cold causes congestion, sore throats, sneezing, and more. It can also vary greatly in severity.

After spending a decade working in shelters, I’ve sadly seen a lot of upper respiratory infections in cats.

In some cases, the congestion can get to the point where cats find it easier to breathe through their mouth instead of their nose. Most cats won’t do this for long periods of time and instead it’s usually done for a few moments.

If your cat has an upper respiratory infection that’s leading to open mouth breathing then you’ll likely know it. They’ll be congested enough that you can hear them breathing but other issues like nasal polyps can cause congestion.

Cats that are breathing through their mouth will open and close their mouth in an almost gulping movement. If you’re seeing anything like this, it’s important to consult your veterinarian as soon as possible.

Check Also: 4 Causes Why A Cat Sounds Congested But No Discharge

Should You Worry About Weird Mouth Movements?

Weird and unusual mouth movements aren’t something to just blow off but you also shouldn’t jump to conclusions and immediately assume that your cat is suffering from a rare condition.

For the most part, if your cat is chattering at birds or reacting to something smelly then there’s likely nothing to worry about. Not only are those the most benign explanations for strange mouth movements, but they’re also some of the most common.

Every other reason on this list could be a cause for concern and a good reason to visit the veterinarian. However, if you’re ever unsure, it’s always a good idea to consult your veterinarian.

You can get a better idea of what explanation may make the most sense for your cat by understanding the context behind the mouth movements. If it occurs every time they see a bird outside the window, then you can feel pretty confident that it’s a chattering response.

If it happens after they smell your dirty sock, then we’re probably looking at the Flehmen Response and if it’s after chasing their favorite toy up and down the stairs then it might be panting.

But if it occurs after eating or at random times then it may be a cause for concern.

If at any point your cat stops eating or you notice other behavioral changes in addition to strange mouth movements then it’s time to consult your veterinarian. 

Frequently Asked Questions

Since this post was published, I’ve received quite a few emails about specific scenarios so I wanted to add a quick section to address them!

Why Does My Cats Jaw Quiver?

Cats will quiver their jaw in response to severe dental pain. This most often occurs during an exam when a particularly painful tooth is evaluated or when something firm like kibble hits the tooth. However, cats may also take on a quivering motion when chattering at birds so it’s important to pay attention to context.

Why Does My Cat Make A Weird Face?

In most cases, that weird face is related to the Flehmen Response where cats will squint their eyes, lift their lips and slightly open their mouth in order to really take in a smell. This weird face allows them to better access their Jacobson’s Organ which helps cats both smell and taste something.

Why Is My Cat Opening And Closing Their Mouth?

This could be anything from a very faint vocalization to open-mouth breathing or respiratory distress. Watch your cat closely and look for any additional context clues to help you understand what’s going on. Since this could be so many things, it’s a good idea to talk to your veterinarian.

My Cat Seems To Chewing On Nothing?

Chewing on nothing could be related to dental discomfort or in some cases cats may actually have something stuck in their mouth that you can’t see. In rarer cases, it could be related to a condition called Feline Orofacial Pain Syndrome.

Closing Thoughts

What might seem like a simple question is actually quite complex and there are many possible explanations for strange, unusual, and weird mouth movements.

In most cases, it’s simply a case of the cat chatters or the Flehmen Response both of which are unquestionably weird.

But if these don’t explain your cat’s behavior, it’s possible that there’s a medical issue at play and that’s where things can get very confusing.

I’ve done my best to give you the resources you need to get a headstart on figuring out what’s going but if you’re ever unsure, it’s always best to consult your veterinarian.

Read Next: Why Is My Cat Purring Constantly?