Dog Holding Its Mouth Slightly Open – What Is The Reason?

Dogs can do all kinds of weird behaviors that surprise and worry us. But what should you do if you saw your dog holding its mouth slightly open?

A dog may hold its mouth slightly open as a sign of relaxation or anticipation. This behavior allows heat dissipation and is akin to humans exhaling. However, it could also indicate discomfort or illness. There are a few other notable reasons for this behavior.

How do dogs communicate through body language?

Dogs have a unique way of expressing their feelings and intentions without saying a single word. Tail wags and ear positions play a vital role in this non-verbal dialogue. You might sometimes find your dog licking your legs to communicate something to you. Sometimes it will jump on you or lay on you to say it misses you.

By interpreting these dog gestures, you can gain insights into your dog’s inner world and strengthen your bond.

Why do dogs hold their mouths slightly open?

Most dogs could be doing this for no specific reason. However, there may be some cases where it is a signal for some health problem.

A sign of relaxation?

Dogs often open their mouths slightly when they’re at ease and content. It’s a peaceful gesture that indicates they’re comfortable in their surroundings. You will often see this behavior when the dog lies down comfortably, sometimes after a harsh exercise.

Could it be a cooling mechanism?

Canines don’t sweat like humans, so they rely on other methods to cool down. Dr. Christopher S. Baird had this to say about dog sweating:

Although dogs don’t sweat profusely and visibly the way humans do, they definitely have sweat glands that secrete sweat in response to heat. The problem is that most dogs are covered with a thick coat of fur, so sweat secreted where there is fur would get trapped in the fur, fail to evaporate, and therefore fail to cool the dog down much. 

Panting is one way to do so and dogs do it by opening their mouths slightly. This will be more noticeable in certain breeds and certain weather conditions. For example, it will be common to see this if you have a Husky living in hot weather. Dogs will also do this during exercise.

Is there a link to nasal congestion?

Sometimes, you will see a dog with a partially opened mouth if it’s experiencing nasal congestion. That makes the dog’s breathing tough it starts using its mouth as a way to breathe more comfortably. The reason for the congestion could be allergies to pollen or dust. Dogs are also susceptible to colds that can inflame the nasal mucosa. 

What other respiratory problems could be a cause?

If your dog is struggling with its breathing and trying to open its mouth to get more air, it could be a sign of a more serious problem. Pneumonia and bronchitis are common inflammations of the respiratory system that cause coughing, wheezing, and fevers. A collapsed trachea is a disease common in some dogs. Dr. Ned F. Kuehn from the MSD Veterinary Manual describes this disease as such:

Tracheal collapse is most common in toy and miniature breeds of dogs, although it may occasionally occur in large-breed dogs. The cause is unknown. Affected dogs have a dry, honking, chronic cough, and labored breathing. They can have trouble breathing during inspiration or expiration. 

What about cases of mandibular paralysis?

Trigeminal neuritis, or mandibular paralysis, is a disease that causes paralysis of the dog’s facial muscles. It does this by causing inflammation on one of the essential motor nerves for chewing. Because the dog won’t be able to control its muscles, it might keep its mouth open while also being unable to chew.

Could the problem be dental issues?

Other reasons for dogs holding their mouths slightly open include problems with teeth. Having an infection, or an abscess in the tooth might cause tremendous pain to your dog and prevent it from closing its mouth. Tooth cavities are another common reason, and you will often see the dog feeling pain when eating or drinking.

Maybe nausea is the problem?

If a dog is feeling nauseous and has a feeling of needing to vomit, it will keep opening its mouth, even if that doesn’t happen. It can get nausea from gastrointestinal infections, bloat, and ingesting toxins. Besides having its mouth open, your dog might also lick its lips, drool, and swallow more frequently.

Are there misconceptions about dogs with open mouths? 

Seeing open-mouthed dogs might be scary for some people, especially if the dog has a big mouth. Some interpret it as a sign that the dog is feeling angry and will react aggressively. This is especially frightening for dogs that are known for a strong bite. For example, the Belgian Malinois psi is 190, and this is a dog with a relatively weak bite compared to other breeds. Luckily, the dog with an open mouth probably has some other reasons for doing so instead of biting.

How should you prevent your dog from doing this?

Most of the time, you should not do anything if you catch your dog with an open mouth. If it seems relaxed, it just might be the best pose for lying down, so just leave it be. That said, there are some other things you can do to prevent any future problems.

Keep the temperature low

If the reason for this canine behavior is heat, and you are currently experiencing summer weather, it is best to help cool off the dog. Make sure you don’t go out during the hottest hours of the day and instead choose late evenings for the daily walk.

Then, you should also invest in a good cooling fan that will keep your house temperature low. Taking the dog for a swim in your home pool may also help bring its temperature down. You can also try making some frozen fruit and give them as treats from time to time.

Brush its teeth regularly

When you notice that your dog is holding a partially open mouth, consider looking inside it to check the teeth. Big cavities can be seen with the naked eye and will alert you to take your dog to a dentist.

To prevent these from appearing altogether, you should keep in mind to brush your dog’s teeth regularly. “Ideally, you should be brushing your dog’s teeth at least once a day, with many vets recommending that they should be brushed twice daily.”, according to the the CDHP Dental Health Project. If you can’t do it that often, three times a week is the minimum amount required to maintain the dog’s dental health. Any additional symptoms and problems should be advised by a vet.

happy dog with its mouth open

Dog holding its mouth slightly open – A summary

Once you see your dog’s mouth in this position, it might worry you. But most of the time, there will be no reason for doing so. Some dogs just relax like that, and others might do it because it’s part of the happy dog expressions. Then, some dogs might only feel warm and need to cool off a bit to get back in shape.

That said, there are serious reasons why it might be doing this. If it seems to you that your dog is having a teeth problem, it is best to take it to a dentist. Have in mind to brush them regularly and use a proper toothbrush. If the dog is experiencing any immediate symptoms, you should take it to the emergency room.


Why do dogs open their mouth while playing?

This is a normal behavior in dogs known as mouthing. Puppies usually do this as a form of play and to release energy. It is a great way for them to learn how to control their bites and not hurt their loved ones.

What causes excessive panting in dogs?

If you notice your dog holding its mouth slightly open and panting, it might be because of overexertion or exhaustion. Being in a hot environment also doesn’t help. Respiratory problems can also cause this

How can you help your dog with asthma?

The best thing to do is to take the dog to a vet and listen to their advice. Often, they will prescribe a combination of medications that can help. Avoid using diffusers and essential oils like patchouli oils that will harm dogs.

More dog behavior resources

Here are a few other resources talking about other unusual behavior in dogs and how to deal with them.

You can find a lot more information on weird dog behaviors on our site Dogisa!

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