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The Reasons Why Your Bearded Dragon Sits With An Open Mouth, Crazy

A photo of a bearded dragon with its mouth open

Getting a pet bearded dragon is an amazing experience. They have really special and individual personalities and also some, what can seem, strange tendencies.

One of these strange behaviours that I have seen and have heard many other owners talk about is bearded dragons with their mouthes open. No, I’m not talking about eating with their mouths open. What we are talking about is sitting still with their mouthes fully opened.

To a new owner this can obviously be quite scary and worrying but do not worry. In this article I am going to tell you all of the main reasons why it happens, what it means and also what you can do to remedy it.

To show you what I am talking about here is a quick video from YouTube showing a bearded dragon with its mouth open. Just so you know this beardie is actually temperature gaping but more about that later on!

Why do bearded dragons keep their mouth open?

First off I want to give you the quick answer to the question. I will then go into further detail about all of the different reasons and also how you can make changes to stop it from happening.

So why do bearded dragons sit open mouthed?  A bearded dragon may keep its mouth open for a number of different reasons these include temperature regulation, which is known as gaping, yawning and stretching. They are also known to use it as a sign of defence and aggression. Finally it can sometimes also be a sign of a respiratory infection 

Now that you know the reasonings read on to find out why it happens and what you can do to help.

Temperature gaping.

This first one is the most common reason and so I will start here. It is also nothing to drastic and you do not need to worry about it to much.

Temperature gaping or as it is sometimes known just “gaping” is when a bearded dragon sits with its mouth wide open, usually when basking.

Because bearded dragons are cold blooded lizards they cannot cool themselves down by sweating like we do. Instead they can regulate their temperature by sitting with their mouths wide open. Kind of like the way that a dog pants when it gets hot.

The bearded dragon can release the excess heat that is building up in its body. Gaping is nothing to worry about as long as the temperature of the tank is right.

In actual fact a bearded dragon with its mouth open gaping is a happy beardie. This shows that it is not to cold and is fit and healthy and can thermoregulate its own temperature.

How to tell if your bearded dragon is temperature gaping.

This one is fairly easy and straightforward. If your bearded dragon is sat with its mouth open after basking in the heat for an hour or so it is more than likely gaping.

You will usually see this happen when it is directly under or above the heat source and is just taking a moment to cool down and chill out.

It really is nothing to worry about but if you notice it happening a lot more frequently just check the tank temperature for peace of kinds sake.

Yawning and stretching.

Yep this really is a thing! Just like you and me bearded dragons love to have a good stretch and a yawn. They especially love to stretch their beards, I guess it just feels so good.

This can also happen around the time that your beardie is about to, or in the process of shedding. The skin around the face is usually the toughest to shed and is quite often where it all begins.

By opening its mouth wide your bearded dragon is stretching the skin and helping it to break away. Again this is absolutely nothing to worry about.

Defence and aggression.

Another reason why your bearded dragon may have its mouth open is because it is showing signs of defence or aggression. This is something that can be quite a problem if you enjoy handling your beardie.

As any experienced keeper of bearded dragons will tell you, they as a pet are quite docile and loving in their own way. This doesn’t however mean that they cannot be startled.

Usually the way it goes is that the owner accidentally creeps up on the beardie and startles it. The beardie then puffs out its beard and opens its mouth wide, acting like it is a big and scary beast. The owner then grabs the bearded dragon and receives a bite on the end of the finger!

As you can imagine this is not a nice situation to be happening on a regular basis. However do not despair there are steps you can take to stop this, read on to see how!

What you should do if your bearded dragon is showing defence and aggression signs.

If your bearded dragon is getting spooked a lot and then threatening you with an open mouth and puffed out beard there are a few things that you can do.

Adding extra hideouts and plants/trees into your bearded dragons tank can help to alleviate its stress levels. It will feel like it has more privacy and is all together much safer from predators. This can in lots of cases stop the threatening and defensive behaviour.

Another way to stop this from happening is to learn safe handling and pick up techniques. If you want to know more about that I have a a full article that explains more.

Respiratory infection.

Ok so the last reason for a bearded dragon having its mouth open is respiratory infection and unfortunately this is the worst. However rest assured it is not that common and the chances are that your beardie is displaying the behaviour for one of the reasons above.

The chances of your bearded dragon developing a respiratory infection are increased exponentially if the tanks humidity level is 40%+ for a prolonged period of time.

Try to keep your bearded dragons tank at around 30-35% humidity to cut off the chances of a respiratory infection. These humidity levels replicate the dry air or their natural environment.

How to know if your bearded dragon has a respiratory infection.

If your bearded dragon has a respiratory infection you will notice it sat still with its mouth open for very long periods of time. It is not trying to cool down but instead is trying to breathe through its mouth.

You may also notice mucus around the mouth and nose, more so than normally present. Other symptoms of respiratory infection include:

  • laboured breathing.
  • weezing.
  • lethargic and slow movements.
  • loss of appetite for all foods. Make sure you buy the right food.

If you notice any of these symptoms it is important to rush your beardie to your vet. Leaving the infection can cause a build up of mucus in the lungs which can eventually suffocate your beardie.


In most cases a bearded dragon with its mouth open is nothing to worry about and is normal behaviour. Keep an eye out for any infections but otherwise try not to worry.

Just enjoy watching your bearded dragon exhibiting one of its many strange behaviours!

Related questions.

My bearded dragon has its mouth open and its eyes are also bulging is this normal? Do not worry, yes this does seem strange but it is pretty normal. When a bearded dragon is going to shed its skin it stretches the old skin around its face by opening its mouth and also bulging out its eyes. If you would like to know more have a read of this article that I wrote on the subject.

My bearded dragon is sat looking at me with its mouth open and waving its arm, what is wrong? Again this is another strange behaviour that we see in bearded dragons a lot. Your bearded dragon is showing signs of fear towards you. I recommend having a look at the guide I wrote about this exact behaviour, you can find it here.