
Cats are interesting creatures to watch and observe, even while they are sleeping. You might have ever seen your cat breathing with its mouth slightly or half opened.
It can be a rather strange behavior to notice.
But should seeing your cat with its mouth open be a cause of concern for you?
Cats can breathe with their mouths open for a number of reasons. There are times when your cat is trying to gather more information about a particular scent that caught its nose. Other times, a cat’s mouth which is open could signal respiratory distress in the cat such as feline asthma or a heart condition.
In this article, we will be looking at a number of reasons that might cause your cat’s mouth to be opened and what you should be doing about it.
What Is The Flehmen Response In Cats?
I am going to start off with a very common biological behavior that is found in cats.
When a cat exhibits the Flehmen response, it basically means that it’s noticing and taking note of a certain smell, scent or odor.
This can be observed when a cat keeps its mouth open slightly after a long sniff.
You might even see your cat exhibit this look when it’s smelling your breath which consists of many interesting odors.
Most of the time, this is done to ‘capture’ the pheromones in another cat’s urine. But the cat will also do this when it is intrigued by an interesting scent.
Deciphering Pheromones
Many cats communicate with other cats by using pheromones. Each cat has its own unique pheromone signature which tells other cats different messages.
Pheromones are used when cats are marking their territories or when they are ready to mate.
Cats can decipher the pheromones of another cat by touching noses and analyzing the odors of the other cat.
We, humans, have our own pheromone signatures as well. Though not as complex as that of an animal as we have evolved to use other methods of communication, it still plays a part in our lives.
A cat is able to trap the pheromones of other cats in its tongue and then transfer the pheromones to the roof of its mouth where a duct exists.
When a cat does this, it looks like it is sneering which adds a touch of comical adoration to its face.
An interesting fact is that a male cat exhibits the Flehmen response more often than a female cat.
This is due to the higher levels of testosterone in male cats which makes them more attuned to weeding out fertile females for mating.
Jacobson’s Organ
“This allows the cat to ‘smell the taste’, so to speak.”
The Jacobson’s Organ or the Vomeronasal Organ are sensory structures in your cat’s mouth that allow the Flehmen Response to happen when a cat keeps its mouth open after smelling something peculiar.
The cat will curl back its upper lip resulting in a silly-looking sneer or ‘stinky face ‘that a cat does during the Flehmen Response.
By keeping its mouth slightly open, the cat draws the pheromones or scent particles through its mouth rather than the nose.
The scent is then analyzed and broken down by the Jacobson’s Organ and transmitted to the cat’s brain.
This action happens more frequently with unsterilized or feral cats during mating season.
Author Jogn Bradshaw mentioned in his book Cat Sense that the Jacobson’s Organ allows cats to process smells differently than just ‘smelling’ them.
It is probably hard for us cat owners to understand what goes through our cat’s minds when this happens as we do not possess this ability.
This allows the cat to ‘smell the taste’, so to speak. Hence the way to a cat’s stomach is through its nose as they have no tastebuds.
Should I Be Concerned About The Flehmen Response?
Not at all.
It is a very normal and natural response for cats. Just like how we breathe and analyze smells.
It’s just one of the many weird cat behaviors that our feline friends do from time to time.
However, pet owners should know how to differentiate a Flehmen Response vs panting. A cat can pant when it is tired.
The cat will have its mouth open and tongue partially hanging out while taking shallow and rapid breaths.
Why Is My Cat Engaging In Open Mouth Breathing?
As mentioned above, it is normal for many cats to breathe with their mouths open after an intense playing session, chasing prey or when it’s stressed.
However, if such breathing is a common occurrence in your cat’s behavior, that could be a signal of more serious medical conditions.
1. Asthma
Cats can also get asthma, like us humans. It is basically a chronic inflammation of the lungs.
Asthma in cats is triggered by stress or specific allergies, causing the cat acute respiratory distress.
Symptoms of feline asthma include:
- Wheezing
- Huffing and puffing
- Coughing
- Rapid breathing
- Open mouth breathing
- Sleep with mouth open
Feline asthma is a condition that can be managed with medication from the vet.
The most common form of treatment is by using corticosteroids to reduce inflammation in the lungs and dilate the air passageways.
2. Heart Issues
“Cats can get heartworms from a mosquito bite.”
If your cat has an existing or undetected heart condition, it can cause your cat to pant.
This can happen to kittens and not just to a senior cat.
There’s a genetic condition where a cat can have weakened heart muscles which makes it difficult for the heart to pump blood efficiently throughout the body.
Signs of heart disease in cats include:
- Weight loss
- Lack of appetite
- Sudden collapse
- Difficulty and rapid breathing
- Rear legs paralysis
Other ailments such as heartworms can cause heart problems in cats.
These parasites will reside and reproduce in your cat’s heart. Cats can get heartworms from a mosquito bite.
When an infected mozzie bites the cat, the heartworm eggs or larvae will be passed on to the cat.
The best and fastest way to fill these parasites is to get some deworming medication from your vet.
3. Feeling Too Hot

Cats are able to regulate their body temperature via their ears, paws and licking themselves.
If you were to touch your cat’s ears on a hot day, the ears will feel pretty warm due to the increased amount of blood flow to that area.
There can be days when the heat is too much for them.
Symptoms of an overheating cat include:
- Panting
- Lethargy
- Drooling
- Bright red gums
It can be very easy for a cat owner to overlook heatstroke in the cat especially if it’s indoors but it can happen.
If you see your cat engaging in open mouth breathing on a very hot day, cool down the room by drawing the shades, turning on the aircon and rubbing down your cat with some cold water.
Heat exhaustion in cats can be fatal so please be more mindful of your area is going through a heatwave.
4. Feeling Stressed And Anxious
A cat can start panting when it’s feeling stressed. This can be due to an external scenario that it feels helpless in.
For example, being in a carrier and going to the vet, being near other animals that it is fearful of.
There’s not much that you can do if you are bringing your cat to the vet.
You can try putting your used t-shirt in the carrier to see if your smell calms it down.
The first time I ever saw my cat breathing with its mouth open was after his dental procedure.
He was feeling very anxious after the whole thing which made me very concerned.
I later found out that the vet extracted a number of my cat’s teeth without even telling or asking me first.
It was supposed to just be a cleaning procedure but some teeth were removed due to gingivitis.
No wonder my poor cat was in so much distress.
In circumstances where you can remove your cat from the stressful situation and keep your cat calm, please do so as quickly as possible.
Needless to say, I never brought my cat back to them ever again.
5. Feline Cold
Your cat can catch a cold just like how humans do. The cold can be caused by a viral or bacterial infection.
The most two common causes of cold in cats are caused by Feline Herpesvirus and Feline Calicivirus.
These viruses are very contagious and can spread like wildfire in pet shelters or homes with multiple cats.
When a cat catches a feline cold, it will have an infected respiratory tract.
This can cause symptoms such as:
- Coughing
- Sneezing
- Open mouth breathing
- Watery eyes
- Nasal Discharge
- Mild fever
- Sleeping with mouth open
Most healthy cats are able to recover within a week or so. But if your cat is a kitten or a senior cat, it might be a good idea to take it to the vet for medical treatment.
If your cat has a weaker immune system, it is better to get it resolved ASAP to prevent further complications.
6. Anemia
This is a disorder that affects the red blood cells in your cat’s body. This results in less oxygen being carried in the bloodstream thus leaving your cat feeling breathless.
Anemia in cats can happen due to the following causes:
- Loss of red blood cells
- Red blood cells being destroyed
- Unable to produce enough red blood cells
The above problems can be due to heartworms, congenital abnormality, internal bleeding, toxicity, etc
Symptoms of anemia in cats include:
- Lethargy
- Sleeping and hiding more than usual
- Gums turning white or yellow
- Difficulty breathing
- Open mouth breathing
- Black stools
- Loss of appetite
Why Is My Cat Panting With Its Mouth Opened?

As mentioned above, there are many reasons that can cause your cat to be panting with its mouth open.
It could be that your cat is feeling really warm or it could have some form of respiratory distress that you are not aware of.
Due to the potentially serious health implications of prolonged or frequent panting in cats, it’s highly recommended to seek immediate vet care if this symptom persists beyond a day.
Here at Petsbeam.com, we are firm believers in getting your cat treated sooner than later.