Top 4 Reasons Why Bearded Dragons Open Their Mouths

Bearded Dragon Mouth OpenBearded dragon? Open Mouth? Don´t worry, don´t worry! Most probably your bearded dragon is not sick if he stares at you with an open mouth looking like he is ready to spit a fireball right into your face.

The reasons why bearded dragons open their mouth are mostly not alarming. Most of the time bearded dragons do that to regulate their body temperature. It can also be a sign for aggression or defensive behavior.

This article will show you 4 reasons why your bearded dragon shows an open mouth all the time. It will show you, what you can do about it and why it is important to know what your bearded dragon wants to tell you with this behavior.


The first and most common reason for a bearded dragon’s open mouth is called “gaping.” Any dragon kept at the right temperature will gape frequently while they bask.

It is a form of thermoregulation in which excess heat is vented out of the mouth—the first defense against overheating. Where humans sweat, bearded dragons gape. However, the behavior isn’t a sign of discomfort.

In fact, they do this to prevent heat buildup once the perfect internal temperature is achieved. A gaping bearded dragon is a happy bearded dragon—not too cold, and, due to their personal ventilation technique, not too hot!

How To Tell If Your Bearded Dragon Is Gaping

“So, okay. My sweet, darling lizard is probably fine, just gaping… But what if I’m wrong? What if I’ve mistaken a symptom of some insidious disease for gaping?”Calm down, there’s a simple answer to this.

If a bearded dragon has been basking for a couple of hours, and that’s when you notice the opened mouth, then the likelihood of gaping is huge!

Throw your worries out the window. However, there are other possibilities to consider when a chilly dragon opens his mouth.

Beard Stretching And Yawning

Beard stretching, puffing, or flaring is another normal behavior for bearded dragons. But, to the unprepared witness, it may appear that your bearded dragon is experiencing a demonic possession, or—for the realists out there—like its choking.

Despite the freakish head movements, frog-like beard puffing, and erratic opening and closing of the mouth, there’s no need to panic. This is simply how a bearded dragon stretches his/her beard.

Bearded dragons also yawn, which looks like… well, a yawn. It is sometimes accompanied by a small beard stretch.

Aggression And Defense

As most of us know, bearded dragons are docile, friendly reptiles. Aggressive behavior towards humans is rare. However, you may find that you’ve triggered defensive behavior in your pet.

Once, I startled my lizard by towering over him during a trip outside, which usually leaves him nervous. He quickly turned towards me, mouth opened, beard puffed out, displaying his best impression of a fearsome creature that’s ready to pounce.

After a moment, he realized I was the same human I’ve always been and allowed me to sit down. Aggressive bearded dragons are not unheard of, though. And after having my finger mistaken for a worm, I can attest to their jagged little teeth.

While a beardy could never take your finger off, they’re capable of inflicting a nasty cut.

Always respect the animal’s body language. Aggressive dragons might puff, hiss, leap, and gape. But most of us will never see this. Generally, only dragons that have a bad history with humans will ever act this aggressively.bearded dragon open mouth

What To Do In That Case?

If you think that your bearded dragon opens its mouth because it shows a defensive behavior towards you, it can help to create a safe place for your bearded dragon.

For example, get these plants and cover two or three sides of the bearded dragon inclosure with plants.

This way your bearded dragon can´t see what´s going on around its tank and this helps extremely to calm down an aggressive or scared bearded dragon. You can also get a background like this to cover a side of the beardie tank.

Another great way to make the beardie tank for comfortable for your bearded dragon is to get a hide. I recommend to get this hide. It is cheap, you can choose the size you need and it gets the job done perfectly.

Bearded Dragon – Respiratory Infection

The final reason for bearded dragons to have opened mouths is the only reason for concern.

Respiratory infections are caused when humidity exceeds 40% for a prolonged period.

Bearded dragons are animals of the dry woodlands of Australia, not adapted to breathe moist air, making respiratory infections common in humid regions.

Keepers should own a hygrometer and use these methods to maintain low humidity in enclosures: If you use a water bowl, keep it small and away from heat sources.

Don’t use barks or mosses in terrariums, as they retain moisture. If the humidity is high in the enclosure, add more ventilation.

If the humidity in your house is too high, and no other methods work, buy a dehumidifier to place in the room with your bearded dragon.

How To Tell If Your Bearded Dragon Has A Respiratory Infection

A bearded dragon with a respiratory infection might look like it’s gaping all day. This won’t be in response to basking temperatures, instead, the dragon is attempting to breath through it’s mouth.

Watch for mucus in or around the mouth and nose, labored breathing, wheezing, or crackling with each breath.

Sick dragons may become lethargic and lose appetite.

Contact a vet immediately if you suspect your dragon has a respiratory infection, as there’s no effective way to treat it at home. For bearded dragons left untreated, fluid will build up in the lungs, eventually suffocating the lizard.bearded dragon with an open mouth


So, why do bearded dragons open their mouths? Bearded dragons open their mouths as a response to many different things, and most of the time, there’s no reason to worry.

Gaping is a good sign when it comes to basking, and they stretch their beards just to, uh, creep us out?

But sometimes it can be a sign of stress, defensiveness, or—worse yet—severe illness. When you pay attention to the dragon’s normal behavior, it will be easy to distinguish one of these things from another.

For those who care for their bearded dragons, and act on their best judgement, I’m sure everything will turn out fine.

Before you leave!

Since I receive many comments and emails from bearded dragon owners that tell me that their bearded dragon is refusing to eat greens, I decided to help with this issue.

What most bearded dragon owners do not know is that a bearded dragon that does not eat greens might be sick or is on the best way to getting sick.

Bearded dragons are omnivores, which means that they eat anything they can find in the wild. The problem that most bearded dragons are picky when it comes to food only arouses due to bad husbandry.

If your bearded dragon is refusing to eat greens, and maybe even only accepts mealworms as food, I highly recommend that you get my ebook: How To Make Your Bearded Dragon Eat Greens Within 7 Days!

After going through the steps outlined in the ebook I will personally check on you and your beardie via email and will support you if needed.

Keep your beardie healthy!


  1. Tamara February 10, 2018
    • Pierre February 10, 2018
  2. Tammy May 7, 2018
    • Pierre July 21, 2018
  3. Ashley H February 9, 2019
    • Pierre February 10, 2019

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