Anybody who owns a Bearded Dragons will have noticed that they often keep their mouths open for long periods of time.

As a Bearded Dragon owner and enthusiast myself, I have done some extensive research into this behaviour and found the 9 reasons why this happens.

So why do Bearded Dragons keep their mouths open? The most common reason why Bearded Dragons open their mouths to regulate their body temperature. They do not sweat and opening their mouth once they reach their ideal temperature stops them from getting any hotter. It is most common to see them opening their mouth when basking.

Read on to take an in-depth look at the 9 reasons why your Bearded Dragon might be keeping its mouth open and find out how you can stop this behaviour from happening.

1# Keeping Their Mouth Open to Regulate Temperature

Bearded Dragons are very clever reptiles and they can display some amazing behaviours to help them overcome all sorts of situations.

One of the behaviours that they often display is opening their mouth for long periods of time which is also known as “gaping”.

This helps them to regulate their body temperature and stop them from getting any warmer when they get their optimal temperature. This can be backed up by the beardeddragon.org who also say this is a common reason why Bearded Dragons keep their mouths open.

If you see your Bearded Dragon sitting under its basking bulb and “gaping” there is usually nothing to worry about.

This is perfectly normal for your Dragon to do this as they can’t sweat to keep their temperature at the optimal level so this is basically another way of regulating that temperature.

Making Sure The Tank Temperature Is Correct

Even though we have established that in most cases “gaping” is perfectly normal behaviour you still need to make sure that you are providing the correct temperature for your Bearded Dragon.

If their tank is too hot then this will make it hard for them to regulate their temperature and you will also need to provide a cool area that allows them to cool down once they have reached their optimal temperature.

If you want to know more about providing your Bearded Dragon with the correct temperature then take a look my ultimate Bearded Dragon temperature guide

Here is a guide to what temperatures you should be providing for your Bearded Dragon at the different ages of its life.

Please Note: This chart should be used as a guide only. You should always consult your vet.

Bearded Dragon Tank Temperature Guide

Bearded Dragon Temperature Guide
Basking Area 95°-100°F
Cool Spot 75°-80°F
Night 70°-75°F

2# Provide Both Basking Area & Cool Spot

We have already touched on this briefly but you also need to provide a cool area to help your Dragon regulate their temperature, this is just as important as the basking area.

If your temperatures are wrong then your Dragon could be gaping due to not having the luxury of leaving the basking temperature for a cooler area when it needs to.

If you want to know the lighting equipment I recommend for your Bearded Dragon then take a look right here, where I share all my favourite equipment and the best places to get it from.

Checking the chart above and making sure that your Dragons tank has temperatures that are close to these in both the basking area and cool spot will allow you to have the piece of mind that they have the right environment they need to be happy and healthy.

Other Reasons Why Bearded Dragons Keep Their Mouths Open

Although regulating body temperature is the main reason why a Bearded Dragon keeps its mouth open, there are also many other reasons and situations where you could see your Bearded Dragon display this behaviour.

Let’s take a look at these situations and if they are unhealthy to your Dragon.

3# Keeping Mouth open Due to Beard Stretching

Some Bearded Dragons will open their mouth to stretch their beard. This behaviour is common when they are close to shedding their skin.

They might also puff up their beard in further attempts to loosen the skin around their beard and head.

This is perfectly normal behaviour and just helps the shedding process.

Beard stretching doesn’t always happen before shedding, sometimes they feel like stretching the beard is something they just need to do.

4# Keeping Mouth Open Due to Aggression

Bearded Dragons are usually placid reptiles but if they do get aggressive for some reason It’s common that they will open their mouth as part of that aggressive display.

There will usually be some other behaviours that your Bearded Dragon will show if they are acting aggressively.

Look out for things like:

  • Fast head bobbing
  • Puffed up beard
  • Black beard
  • Hissing
  • Tall stance

Your Dragon might not show all of these behaviours but if they are opening their mouth aggressively then it would be unusual if they didn’t display at least one of these.

Providing your Dragon with a habitat with lots of hiding places can limit aggression as most of the time they display this behaviour when they feel threatened. 

Here’s a great post where I list all the items you need to create a great habitat for your Dragon so they can feel both happy and safe.

Let’s look at the situations where Bearded Dragons can feel like they need to act aggressively.

5# Keeping Mouth Open Due to Another Bearded Dragon

If you have two or more Bearded Dragons in the same tank then it can cause a lot of problems.

Bearded Dragons prefer to be alone and sharing their living space with another Dragon often results in a quest for power.

One of the Dragons will usually try and become dominant over the other one and opening the mouth in an aggressive way to show how mean and tough they are is common.

If you have two Bearded Dragons housed together and you see this happening then you really need to split them up as soon as possible.

The less dominant one can end up getting very stressed, losing their appetite and even not being allowed to bask by the more dominant Dragon.

Sometimes you could even need to split them up into different rooms because if they can still see each other then the fight for dominance can carry on.

As a very last resort, if you simply don’t have space for 2 tanks in your house or you can’t do it for some other reason then you will just have no other choice but to give one of the Bearded Dragons away.

This might seem cruel but it’s actually the kindest thing to do because keeping two dragons in the same tank when one is dominant is very harmful to the other one’s health.

Here’s a post that explains everything you need to know about housing more than one Bearded Dragon in the same tank.

6# Other Pets Causing Aggression

It can also be quite common that if you have other pets in your home such as cats or dogs that your Bearded Dragon can become aggressive towards them.

Usually, if a Bearded Dragon is uncomfortable with a larger pet in the home they will be frightened or intimidated but some Dragons can actually become aggressive too.

If you notice your Bearded Dragon opening its mouth in an aggressive way towards your pets then once in a while then it’s really not a problem as it might be something simple like your dog was too giddy and caused your Dragon to feel uncomfortable with its presence.

On the other hand, if this behaviour is happening every time your pet is in the room then you might want to think about taking some action as the constant stress levels can be too high in this situation.

There are really only two things that you can do, the first is to stop your pet coming into the room that your Bearded Dragon is in.

This can often be hard, especially if your Bearded Dragon is in the main family room such as the living room.

The other thing you can do is to move your Dragon to another room in the house that your pet is less likely to go in.

This can also sometimes be hard depending on the size of the tank and if you can fit it in another room.

You will have to do what is best for you and your pets. The main thing is that they are both happy and safe.

I’ve written a great post here that shares how Bearded Dragons and dogs can play together and the potential dangers you need to look out for.

7# Small Object & Children’s Toys

This seems quite bizarre when you first think about it but children’s toys and small objects such as socks can cause your Bearded Dragon to act aggressively.

It’s very easy for a Bearded Dragon to mistake a small toy for a predator and they can often act aggressively and keeping their mouth open is part of that behaviour.

Usually, you will also notice hissing or other behaviours that we talked about earlier.

New ornaments and such can also be something that your Dragon can find threatening.

Toys and clothing are usually moved pretty quickly so they don’t cause a problem for a long time, however, ornaments are often placed in one spot and stay there so if you suspect that it’s causing a problem for a long period of time then you will want to consider moving it.

8# Placing The Tank Near The Window

Placing your tank near the window can be wonderful for your Bearded Dragon. They can get so much stimulation from the outside world.

Things like seeing the clouds move and seeing the trees rustle in the wind can help emulate their natural habitat.

Depending on where you live it can also be a scary place and you can often see your Dragon getting aggressive towards whatever it is seeing on the outside of the window.

Animals like cats and birds can cause your Dragon to feel threatened and then they can aggressively open their mouth.

Again, if this is only happening once in a while then its nothing to worry about but if it’s happening daily then you will want to consider moving them away from the window.

9# Keeping Mouth Open Due to Mating Season

There are certain times of the year when your Dragons hormones will be raging and they can get aggressive.

They can keep their mouth open in an aggressive manner for what seems to be no apparent reason.

Sometimes if you try and handle them they can even try and get aggressive with you the owner.

They will often become very territorial and become aggressive when people or pets get come anywhere near their tank.

This is just natural behaviour and there is little that you can do about this. The good news is that once the hormones have settled then everything should be back to normal.

10# Respiratory Infection

Most of the time when your Bearded Dragon keeps its mouth open for long periods of time it will be due to regulating body temperature, however, there is a small chance that they could have a respiratory infection. Terrarium Quest also talks about this in their post on bearded dragon behaviours.

If a Bearded Dragon gets this kind of infection it’s usually due to the humidity in the tank. They are used to low humidity in the wild and high humidity in their tank can cause them problems.

The best way to monitor the humidity in the tank is to get hygrometer. This will allow you to accurately check the humidity in the tank at all times.

I actually recommend using a digital contactless one. Here I share the exact model I use and why I recommend you use it too.

If you don’t want to read the post & review then you can check out the latest price of the thermometer over on Amazon…

If the humidity in your Bearded Dragons tank in higher than 40% for a long period of time then this isn’t ideal for your Bearded Dragon.

There are some factors you need to be aware of that can increase the humidity of your Dragons tank such as using things like bark as a substrate or even decor because it often holds moisture and increases the humidity in the tank.

If you are struggling to keep the humidity low in the tank then try and take out or substitute things that hold a lot of moisture (except the water bowl).

Having a smaller water bowl is another a good idea if you are having problems with the humidity level.

You should also keep any bowls and water sources you have away from the heat source/basking bulb as this will increase the humidity as well.

Generally keeping humidity levels low should be relatively easy but this can depend on where you live and you home. If you are still struggling after the implementing the tips above then purchasing a dehumidifier should stop the problem completely.

If you are ever worried that your Bearded Dragon has a respiratory infection then i recommend that you go and get advice from a Vet, who can see your Bearded Dragon and give a professional opinion.

Wrapping Up

I hope this article has answered all your questions as to why Bearded Dragons keep their mouths open.

I have tried to address all the different situations and how to approach them.

Usually, your Bearded Dragon will open its mouth for long periods to regulate its body temperature so making sure you have the correct temperature in their tank is a must.

There are also lots of other situations where your Dragon can display this behaviour so knowing these situations in advance will help you be able to make an educated decision about what to do.

If you are even worried that your Bearded Dragon is ill then it’s advisable to seek the advice of a Vet who can give a professional opinion.

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