• Beardie Bliss

Why Does My Bearded Dragon Open His Mouth?

Anyone who has interacted with a bearded dragon must have observed this behavior at some point. It is normal to be wondering what to make out of it. Are they uncomfortable, in pain, need your attention, or just going through normal beardie processes?

Today, we will explore the different circumstances that make a bearded dragon open their mouth. Knowing this information will put you in a better position to determine if there is any action required on your part and whether it warrants a visit to the vet.

australian beardie dragon with open mouth outdoor

What Makes a Bearded Dragon Open Its Mouth?

Regulating Body Temperature

This is the most likely reason your beardie will keep its mouth open - to cool its body down. Bearded dragons don’t have sweat glands, so they can’t generate sweat to cool down like humans. This bearded dragon behavior is called gaping, and the open mouth acts as a vent for excess heat.

It is the bearded dragon’s natural defense against overheating. Being native desert dwellers, they thrive in the heat, especially when basking. It is their nature to soak it in and then balance their body temperature using various adaptations.

Gaping should not be taken to mean the conditions are too hot. Bearded dragons are smart enough to move away when the heat is too much.

Staying put indicates they find the conditions in the terrarium just right for basking. The ideal temperature for a bearded dragon’s basking spot is 95 to 110˚ Fahrenheit. The open mouth is how they stop getting warmer once they hit the sweet spot. They will occasionally stick their tongue out for this to be more efficient.

That being established, it is equally important that the tank has a cooler area (between 75 and 90˚ Fahrenheit) where they can retreat to once they are done basking. This way, you are assured the bearded dragon is gaping by choice and not straining for survival.

If they are constantly hiding and seem disinterested in basking, the bearded dragon tank might be too hot and you need some heat regulation. They also generally don’t sleep where they bask. The nighttime temperature should be cooler (70 to 75˚ Fahrenheit), so your bearded dragon gaping at night automatically signals something else going on.

There are other possibilities to consider when your bearded dragon opens their mouth in other areas of the tank away from the basking spot. While they are not necessarily negative, it is important to familiarize yourself with them as a responsible bearded dragon owner. You will need to be attentive to figure out the difference.

Beard Stretching

Like all other animals, the bearded dragon needs to stretch, especially if its muscles have been dormant for extended periods. The numerous muscles on their head and face, including the beard, need periodic stretching, which is also a form of exercise.

Opening the mouth facilitates beard stretching as all these parts move together. Besides the open mouth, they will stretch their neck, raise their head, and sometimes even change beard color in the process. It is common behavior for them to yawn while stretching, just like other animals.

Their beard gets puffed up, and the stretching can be a bit twitchy at times. This is perfectly normal, so it shouldn’t be a cause of alarm on its own. Stretching takes a shorter period than gaping and also comes in handy when the beardie is shedding. It helps loosen the skin around the beard and head.

To Facilitate Shedding Skin

As we have established, the open mouth facilitates stretching and will be more prevalent when your bearded dragon sheds its skin. Stretching and puffing out the beard helps loosen the skin around the head and beard.


The open mouth is also the bearded dragon's natural aggressive posture and can be a defensive behavior. They will use it whenever they panic or feel threatened and hold it as long as the threat exists.

In such instances, it will be accompanied by other impulsive aggressive acts like hissing, a raised beard, fast head bobbing, and a puffed-up chest to grow their profile, so they appear bigger and more intimidating to the perceived threat.

The beard color will occasionally change, or you will note an increased intensity. The posture indicates they are ready to attack.

The activated fight or flight mode will trigger your bearded dragon to pounce on anything that moves in the terrarium, or they will dart out of sight. Fortunately, a bearded dragon bite is not venomous (the kind of venom they produce is harmless), and you can’t get a serious injury from it, although it stings quite a bit.

All the same, letting them stay in this aggressive state for long is stressful and will affect their overall health while leaving them susceptible to disease.

The cause can be anything from your other pets approaching the cage or scaring the beardie with their loud noises, cars passing outside, children playing to unfamiliar small objects like toys, ornaments, decorations, and clothing they mistake for predators.

You should remove the stressor as soon as you identify it and find ways to calm down your beardie. There are instances where you might be perceived as the aggressor due to actions or stances you take being misinterpreted by your own beardie. You should give them space for a while and gradually reintroduce yourself, so they don’t associate you with threats.

To make the beardie feel like it’s in a safe space, you can cover the sides of their enclosure that exposes them to the perceived threats using a background that they can’t see through. Some plants will fit in the tank and accomplish this naturally. You can always move the cage to a quieter area or remove the threatening object from the dragon’s view.

calm beardie sitting on young women hand

Asserting Alpha Dominance in the Presence of Another Bearded Dragon

Bearded dragons are extremely territorial. Having more than one in the same environment where they can sense each other is a recipe for competition. One will always try to exert dominance over the other. This might explain why beardies are solitary by nature and are prone to exhibit aggressiveness towards each other.

To intimidate the competition, the beardie will open their mouth and showcase different combinations of aggressive traits like head bobbing, hissing, the extension of a blackened beard, and others mentioned above.

The dragon that is being intimidated might decide to retaliate by also showing aggression instead of retreating. They can also open their mouth and start hissing, and this will easily escalate the situation to a full-blown fight which always results in injury.

The less dominant lizards are more gravely affected. They are bullied out of the basking zone and might develop health issues like a metabolic bone disease. The constant fear of being attacked and forced submission makes them meek; they will hardly eat and will spend most of their time glass surfing while avoiding their basking spot.

Experts advise that you separate your pets if you have more than one bearded dragon as the continuous aggressiveness is not good for their health. Keep them in separate tanks where they can’t see each other to curb the aggressive behavior.

It’s Feeding Time

close up of bearded dragon eating

Once your bearded dragon becomes accustomed to a schedule, it will start anticipating food at a certain time and will be excited to see your hand or food approach. This might be the reason your beardie sits with their mouth open and sometimes with their tongue exposed, ready to pounce on the juicy wax worm you are offering.

It’s the Bearded Dragon’s Mating Season

At this time of the year (normally during summer), they experience a shift in their hormones that makes them more territorial. They get agitated easily and might be extra aggressive towards everything that approaches the tank, including the owner.

At this point, the aggressiveness isn’t the only reason they open and close their mouths; they do it to impress potential mates as much as to scare away competition and intruders.

The only thing you can do about this is handle additional triggers and prevent them from aggravating the situation. The dragon requires more peace and quiet during this time. Fortunately, it comes and goes with the season, and your sweet lizard will regain their senses.

The Beardie Has a Respiratory Infection

This is usually the result of high humidity in the tank, which conflicts with their natural environment. Being natives of Australia's dry woodlands and deserts, bearded dragons are not adapted to breathing moist air and shouldn’t be subjected to more than 40% humidity for long periods. This exposes them to respiratory infections. You should invest in a hygrometer to constantly monitor the humidity level inside the tank.

A respiratory infection compromises your beardie’s breathing capacity. The breathlessness makes them open their mouth permanently in a bid to suck in as much oxygen as possible. They will seem to be gaping the whole day while trying to breathe through their mouth. If left unchecked, this might cause a buildup of fluid in their lungs, eventually suffocating the lizard.

Other respiratory infection symptoms will help you diagnose it from gaping so action can be taken in good time. Their breathing will be labored, and if you listen closely, you will hear wheezing or crackling with each breath.

A buildup of mucus around the eyes, nose, and mouth indicates respiratory complications. These will be accompanied by a noticeable drop in energy levels and appetite. You should get the bearded dragon to your vet immediately if you suspect a respiratory infection because it can’t be effectively treated at home.

close up of green beardie on black background

Closing Thoughts

A bearded dragon’s open mouth is a natural occurrence that shouldn’t raise an alarm under normal circumstances. It is a critical indicator of the state of the beardie’s habitat and how comfortable they are.

Therefore, it is sensible to know how to interpret what its open mouth means in different situations as it could make the difference between life and death for your beloved pet bearded dragon.


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