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7 Reasons Why Bearded Dragons Keep Their Mouths Open

bearded dragon mouth open

Ever wonder why your bearded dragons open their mouths? Is this normal behavior or a sign of illness? You might be surprised that this behavior can give you a hint of what your beardie is feeling. You just have to know what it means to make the necessary adjustments.

Bearded dragons open their mouths for the following reasons: temperature regulation, reaction to incorrect temperature, defensiveness, stretching, presence of respiratory infection, response to other bearded dragons, and metabolic bone disease.

In this article, we will discuss the different reasons why your bearded dragon keeps its mouth open and the things you can do if it is considered abnormal behavior. So read on!

Why Your Bearded Dragon’s Mouth Is Open

The infographic below will help you find out why your bearded dragon is showing this behavior. After that, we will explain the reasons in detail and what you should do.

Why is my bearded dragon's mouth open?

Let us now take a look at the reasons why your bearded dragon is keeping its mouth open in detail.

Note: If you think that your bearded dragon might be sick and keeps its mouth open because of that, it is best to bring it to a vet asap. If there is no vet near you, or if that might be too expensive right now, we recommend booking an online vet. For example, you can book an online vet at Vetster!

1. Temperature Regulation

Bearded dragons open their mouths to regulate their body temperature. It does not necessarily mean that they are overheating or underheating, but they are simply letting out heat through their mouths to reach their optimal body temperature.

As they do not sweat, opening their mouths is the best way to remove excess heat from their bodies. You can usually see beardies opening their mouths when they are basking to prevent overheating.

There is absolutely nothing to worry about when you see them do this as this is normal behavior. Just as long as you do not see them being uncomfortable while doing so.

Info: “Gaping” is the term that is used when a bearded dragon keeps its mouth open for an extended period of time.

why is my bearded dragon gaping?

2. Incorrect Temperature

It is a huge sign that the enclosure has the wrong temperature when your bearded dragon is gaping but at the same time exhibiting hiding behavior.

Another indication of incorrect temperature is when your beardie is on the cool side of the enclosure, but it is still gaping.

This means that the enclosure is too hot, and the heat is already emanating to the cool side. Note the following temperatures for the basking and cool spots:

  • Baby Bearded Dragons
    • Basking Spot: 100-110 °F
    • Cool Spot: 80-90 °F
  • Juvenile or Adult Bearded Dragons
    • Basking Spot: 96-100 °F
    • Cool Spot: 70-75 °F

If you notice that your beardie is gaping and looks lethargic, this means that it has been exposed to the extreme temperature for too long and is possibly dehydrated. It is best to give it a soak first, before going to the vet.

In order to prevent this from happening, you can check the temperature of the enclosure daily. You can use an infrared thermometer like this one.

Tip: If you need a new heat lamp, have a look at our guide on the best beardie heat lamps here!

3. Bearded Dragon Is Being Defensive

Bearded dragons are loved by many people because they are such docile reptiles. But at the same time, they can still exhibit defensive behaviors when they feel anxious, threatened, and stressed.

Your bearded dragon may also hiss, puff up, and raise its beard along with keeping its mouth open. It does this to appear intimidating towards the thing that is causing them stress.

It is good to note that beardies are territorial. Therefore, if you have other pets that always seem to approach the enclosure, this can trigger their defensive behavior.

You can see the defensive behavior of a juvenile bearded dragon in this video. Notice that it keeps its mouth open throughout the whole ordeal.

At the same time, if your beardie is not yet trained, it can do the gaping behavior whenever you approach the enclosure, try to clean it or feed your beardie.

Defensive behavior may also happen if you have kids that play near the enclosure or if the tank is near a window and there is a lot of activity outside.

Further, the addition of new decor in the enclosure may make your beardie feel anxious.

It is best to do handling training to tame your beardies and also do precautions such as covering a part of the enclosure with a cloth or keeping the enclosure in a quiet area, so as not to disturb their enclosure too much.

Take note, chronic stress can affect the immune system of bearded dragons.

Tip: Read this article to learn what bearded dragons hate the most. By avoiding these things you can minimize stress for your beardie. Also, this article shows you that your bearded dragon likes you (or doesn’t like you).

4. Bearded Dragon Is Stretching

Yes, bearded dragons also do stretching, but not for the reason you think. They stretch their beards for an incoming shed.

When they stretch their beards, it loosens the skin around the area, making it easier to get a full shed. They can do this before they shed and while they are shedding.

They will open their mouth for a short time, and sometimes, they will also puff up their beards.

bearded dragon opening mouth and making noise

5. Bearded Dragon Respiratory Infection

If your bearded dragon has been gaping for hours on end, paired with other abnormal behaviors, it is likely a sign of respiratory infection.

No need to fret, as if it is caught early, medical intervention can ensure a full recovery.

Usually, respiratory infections stem from a poorly ventilated enclosure as well as prolonged exposure to extreme humidity.

Also, if the tank gets too cold at night and then there is a sudden rise in temperature during the day, it can also lead to respiratory issues.

Make sure that the humidity levels are at 35%-40%. Always keep a water bowl inside the enclosure, and you can also try using a mesh cover at the top or sides.

Besides seeing your beardie gape for a long time, here are other signs to look out for:

It may be difficult to decipher one noise from the other, especially if you are a beginner beardie owner.

You can read this article to know the different noises that bearded dragons make to see if they have a respiratory infection.

If you see the signs we discussed, it is time to go to the vet. Usually, they are given injectable or oral antibiotics. They may also do blood tests and X-rays to properly diagnose the infection.

Here is what gaping looks like when it is due to respiratory infection. In this case, it has already been treated with antibiotics.

6. Bearded Dragon Is Responding To Other Bearded Dragons

Bearded dragons are not social reptiles. This is precisely the reason why it is not recommended to house two bearded dragons in one tank.

It is still possible that things turn out okay as they will try to tolerate each other, but usually, one beardie will assert its dominance towards the other beardie.

When they do this, they will usually gape and puff up their beards to assert dominance.

If the other bearded dragon does not show submissiveness, such as waving its arm, the other beardie will keep on gaping until it is established that it is the “alpha.”

The same goes when two bearded dragons are housed too close to each other, even if they are in separate tanks. As they can clearly see the other bearded dragon, one or both of them will try to size each other up.

Further, they can also do this gaping behavior when it is mating season. During this time, there is a shift in their hormones that trigger them to be more defensive, hence the gaping and the hissing.

Did you know?
Solitary males still exhibit defensive behaviors during mating season even when there are no females or other competing males around.

7. Bearded Dragon Has Metabolic Bone Disease

Metabolic Bone Disease is caused by giving your beardies the wrong diet. This means that they are not getting enough Vitamin D3 or calcium.

At the same time, it is possible that they are not reaping the effects of your UVB lighting so that they can get Vitamin D.

A huge sign of MBD is when beardies seem to gape endlessly. The fact is, they are not actually gaping, instead, they simply cannot close their mouths properly due to swelling in their jaws. Other symptoms include:

  • Swelling of the face or hind legs
  • Trembling limbs
  • Lethargy
  • Lack of appetite
  • Twitching of the muscles
  • Deformities in the body
  • Inability to walk

Therefore, it is essential to have a closer look at your beardies to check if they are actually gaping or if they are keeping their mouths open as they cannot close them anymore.

If this is the case, you should immediately go to your vet.

Tip: Is your bearded dragon acting weird and you are not sure if it could be something serious? Our article here will show you if your beardie might be dying.

They can be injected with calcitonin, fluids, and Vitamin D3. You also need to adjust their diet as well as provide them with proper UVB lighting.

Here you can see how the opening of the mouth due to MBD may be mistaken as normal gaping.

Why Is My Bearded Dragon Sticking Its Tongue Out?

It may look funny or even weird when you see your bearded dragon sticking its tongue out. Do not worry, your beardie is not making fun of you, but this sometimes happens when they are gaping for temperature regulation.

They also stick their tongue out to expel heat from their body. Therefore, this is also another sign to check the temperature in their enclosure to see if it is too hot.

When your beardie sticks its tongue out, it is to expel rapidly a huge amount of air.

They may also stick their tongue out when you first got them and they are still adjusting to their surroundings.

They do this to have a better feel of the unfamiliar objects near them. They can also gape and even hiss while their tongue is out when they feel anxious about the new environment.

why is my bearded dragon sticking its tongue out?

Bearded Dragon Open Mouth FAQ

  1. Why does a bearded dragon open its mouth when it sees food?
    • This behavior indicates anticipation or readiness for feeding. It’s a natural predatory response, showcasing their instinct to hunt and consume prey.
  2. Do bearded dragons open their mouths when they’re in the water?
    • This can be a way of drinking, regulating body temperature, or reacting to discomfort if the water’s temperature is not suitable.
  3. What does it mean when a bearded dragon holds its mouth open and doesn’t move its head much?
    • Often a sign of basking, this helps in thermoregulation. Persistent behavior accompanied by other symptoms could indicate respiratory issues.
  4. Why would my bearded dragon consistently open and close his mouth?
    • This could be normal behavior for temperature regulation or a sign of respiratory distress. Context and accompanying behaviors are key to interpretation.
  5. Why does my bearded dragon open his mouth and hiss in calm situations?
    • This defensive behavior suggests stress or feeling threatened, possibly triggered by environmental changes or the presence of other pets or people.
  6. What does it mean when a bearded dragon has its mouth open with its tongue sticking out?
    • This could be part of their sensory exploration or a way to pick up scents. However, if this behavior is unusual or excessive, it could indicate a health issue.
  7. Why does my bearded dragon sometimes open its mouth when I approach the enclosure?
    • This could be a territorial display or a sign of stress. It’s important to monitor if this behavior occurs consistently and in what contexts.
  8. Is it normal for a bearded dragon to open its mouth wide while breathing or panting?
    • This is normal during basking for thermoregulation. Excessive panting, however, could be a sign of overheating or respiratory issues.
  9. Why is my bearded dragon black with its mouth open?
    • Darkening color combined with open-mouth behavior can indicate stress or a thermoregulation attempt. Consistent dark coloring and stress signs should be monitored closely.
  10. How can I encourage my bearded dragon to open his mouth for hydration purposes?
    • Hydration can be encouraged by gentle misting and providing a comfortable environment. If the dragon consistently refuses to open its mouth, it might indicate a health issue or discomfort with the misting process.

It’s important to remember that while these answers provide general insights, each bearded dragon is unique. Persistent or concerning behaviors should be addressed with a reptile-savvy veterinarian for tailored advice and care.


For the most part, it is normal behavior when bearded dragons keep their mouths open.

It is only when they pair the behavior with other behaviors such as hiding, lack of appetite, lethargy, etc. that it is a case for concern as something may be wrong with the enclosure or your beardie is sick or stressed.

Always check the tank to maintain the proper temperatures in both the basking spot and the cool spot so as to keep the gaping behavior at a minimum.

Also, check the humidity levels to avoid respiratory illnesses.

If your bearded dragon appears to be sick, get your beardie to a vet asap. If you can’t do that, we recommend booking an online vet at Vetster. They have great, affordable service, and offer appointments 24/7. Check out Vetster here!

Additional Resources on Bearded Dragon Care

  1. UC Davis School of Veterinary Medicine – Bearded Dragon Care: This detailed guide by UC Davis School of Veterinary Medicine covers the essential aspects of bearded dragon care, including natural history, husbandry, nutrition, and various care requirements​​.
  2. PetMD – Bearded Dragon Veterinary Care: PetMD provides a comprehensive care sheet for bearded dragons, offering insights into annual care, signs of health, common illnesses, and when to consult a veterinarian​​.
  3. Cummings School of Veterinary Medicine at Tufts University – Feeding and Caring for Bearded Dragons: This resource discusses recent studies on bearded dragon feeding practices and health issues, emphasizing the importance of a balanced diet in their care​​.
Pierre And The ReptileCraze Team
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