Why Do Bearded Dragons Hold their Mouths Open (10 Reasons)

If you own a bearded dragon, you may have noticed that they sometimes open their mouths wide. This behavior can be alarming if you’re not sure what it means, so in this post, we’ll delve into the various reasons why bearded dragons open their mouths and what you can do about it.

The reasons why bearded dragons open their mouth are mostly not alarming. Most of the time beardies open their mouth to regulate their body temperatures. However, it can also be a sign of many other things such as aggression or defensive behavior.

Reasons Why Bearded Dragons Hold Their Mouths Open

Even though keeping their mouth open is not usually a bad sign, you should figure out when he’s doing it to see if he’s in discomfort, anxious, or just trying to regulate his body temperature.

Here are 10 reasons why your bearded dragon might be keeping its mouth open

1. Gaping For Temperature Regulation


Most of the time, when a bearded dragon sits with his mouth open he is actually regulating his body temperature also known as gapping. This means they’ve reached their optimal internal temperature and want to dissipate extra body heat. This behavior is called gaping.

Bearded dragons don’t sweat to regulate their body temperatures like we do. Instead, when they have reached their ideal body temperature, which sits between approximately 95 and 110 degrees Fahrenheit, a dragon will prop his mouth open as to not get any hotter. You’ll see this frequently when they’re basking under a heat lamp.

This is a sign that you’re keeping your dragon at its ideal temperature, so props to you!

However, do make sure that you’re keeping your lamp on only one side of the tank. That way your dragon can escape the heat when they’re ready to cool its temperature. Having a thermal gradient within the habitat so that your lizards can move to a cooler location if they desire, is vital.

How to Tell if Your Bearded Dragon is Gaping

There is a simple answer to tell if your beardie is gaping. If your bearded dragon is basking for a couple of hours and that’s when you notice the opened mouth then it’s most likely gaping.

2. Incorrect Temperatures

Your bearded dragon tank needs to have a warm and a cold side. So, your beardie can move to the colder side when they want to cool down a bit.

If the temperatures inside the tank are incorrect then your beardie could be gaping due to not having the luxury of leaving the warmer side for a cooler area when it needs to.

Read More >> Temperature Gradient for Bearded Dragons

3. They’re Stretching Their Beard

All animals need to stretch their muscles after a period of inactivity. You may see your bearded dragon open their mouth to stretch its beard. You will typically observe your beardie open their mouth briefly as they are expanding their beard.

Bearded dragons also open their mouths and stretch their beards when they are about to start shedding. Around the period of shedding, you might notice your lizard puffing out its beard. Stretching and puffing both assist your beardie in removing the skin from their head and beard.

Even if your lizard isn’t getting ready to shed, bearded dragons frequently open their mouths to extend their beards. Over time, you’ll develop the ability to recognize this!

4. Sign of Aggression


Bearded dragons are generally calm and docile lizards. However, if they feel threatened or angry, they may open their mouths to show aggression.

If a bearded dragon’s mouth is open, they’re baring teeth and you see a dark beard, this is a sign of aggression.

When threatened, bearded dragons puff out their chest, raise their beard and open their mouths to appear larger and more threatening. If they feel defensive, they may also display a black beard and quickly bob their head.

5. Respiratory Disease

A less common, but potentially serious problem associated with gaping is a respiratory disease. This means that the dragon has to breathe with its mouth open. This is a bit more common and serious in other reptiles, like snakes, but if you notice this behavior frequently, perhaps it is time to take your pal in for a check-up.

If your bearded dragon is keeping its mouth open accompanied by other signs such as lack of appetite, not willing to move around, mucus around the eyes or nose, coughing, wheezing, or crackling sounds while breathing, it’s time to see a vet.

6. They’re Responding To Another Dragon

Another common reason your bearded dragon might open their mouth is to respond to another dragon. Beardies especially males are territorial creatures and problems can arise if you house them together.

Usually, when you keep two beardies together in a tank, one will try to dominate the other. The dominant one will open his mouth to show dominance over the other.

The less dominant one will become stressed and may stop eating. That is why we don’t recommend housing multiple dragons together.

7. Eager for Food


If your hand or food is nearby, bearded dragons sitting with their mouth open is eagerness for food. No need to worry over this either. You’ll soon see your beardie pounce with their tongues exposed, too.

8. The Tank is Near The Window

Placing the tank near the window can be wonderful for your beardie. They will enjoy things like moving clouds, seeing the trees rustle in the wind, etc. but depending on where you live it can be a scary experience for your dragon.

Animals like dogs, cats, and birds can make your beardie feel threatened, and then they might aggressively open their mouth.

9. Mating Season

During mating seasons bearded dragons usually become aggressive and might keep their mouth open. During this time, bearded dragons become aggressive when people or pets get come anywhere near their enclosure.

There isn’t much you can do about this because it is merely natural behavior. The good news is that everything should return to normal once the mating season is over.

10. Small Object & Children’s Toys


When you first think about it, it seems kind of absurd, but little stuff like socks and toys can make your bearded dragon aggressive.

A bearded dragon can very easily mistake a small toy for a predator, and they frequently exhibit hostile behavior, which includes holding their mouths open.

Typically, the open mouth will be accompanied by hissing if your beardie is mistaking some toy for a predator.

Additionally, your dragon may perceive new decorations and other items as hostile.

Do Bearded Dragons Sleep With Their Mouth Open?

Beardies don’t typically sleep with their mouths open. It might just be a peculiar behavior unique to that particular bearded dragon, but it could also mean that your dragon gets too warm at night. The cage’s temperature at night should be lower than it is during the day, especially where your bearded dragon sleeps.

Why Is My Bearded Dragon Sticking His Tongue Out?

Your bearded dragon might open its mouth and stick his tongue out as well. This is common during gaping and helps him lower his body temperature furthermore to a tolerable level.

Do Bearded Dragons Yawn?

Beard stretching can take many different forms. Your bearded dragon may extend his neck, lift his head, smile, and alter the color of his beard. This would suggest that he is yawning. Furthermore, it is not a cause for alarm that bearded dragons yawn because they do, like the majority of animals.

Why Is My Bearded Dragon Opening And Closing His Mouth?

Your bearded dragon’s continual opening and closing of his mouth could be him expanding his beard and practicing.


Bearded dragons keeping their mouth open is not always a bad thing. There are a number of reasons why a bearded dragon might keep their mouth open. However, most of the time this happens because they try to regulate their body temperature and there is nothing to worry about.

You should keep an eye on your beardie when they start keeping their mouth open because it can also be a sign of serious concern such as aggression, fear, or respiratory infection.

Filled under: Lizards

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