9 Reasons Why Chameleon Keeps Their Mouth Open

Chameleons make fascinating pets. They can be very skittish, prefer to live alone and have eyes that move independently of each other. But what catches most pet owners by surprise is when they find their chameleons just sitting with their mouths wide open and taking deep breaths.

This is commonly known as gaping in reptiles and it is mostly normal. But sometimes it can be the cause of serious concern too.

In this guide, you’ll learn:

  • The common reasons why chameleons keep their mouth open
  • What you can do about it
  • When you should be concerned and see a Vet

What Is Gaping In Chameleons?

Gaping is a behavior that chameleons exhibit where they open their mouth wide and take deep breaths. This behavior can be caused by a variety of factors, including stress, dehydration, illness, or overheating.

When a chameleon gapes, it is trying to regulate its body temperature by increasing airflow to its lungs. This can also be a sign of respiratory distress, which can be caused by respiratory infections, foreign bodies in the respiratory system, or improper husbandry.

Chameleons are highly sensitive to changes in their environment, so it’s important to provide them with the proper temperature, humidity, and ventilation in their enclosure.

If a chameleon is exhibiting excessive gaping, it’s important to consult with a veterinarian who is experienced with reptiles to determine the underlying cause and provide appropriate treatment.

Here Are All The Reasons Chameleons Keep Their Mouth Open

Reason #1 – Your Chameleon is Simply Breathing

Why Chameleon keeps their mouth open

This is the most obvious reason! Chameleons breathe through the Glottis, an opening in the bottom of their mouth. They have a unique respiratory system that is different from other reptiles. Rather than having lungs that expand and contract to breathe, chameleons have a series of air sacs that fill with air when they inhale.

By keeping their mouths open, chameleons can increase the flow of air into their air sacs, which helps them breathe more easily. Slow and steady breathing, even with the mouth open, means a healthy chameleon. If not accompanied by mucus formation or big gulps of air, there is no reason to worry.

Reason #2 – Your Chameleon is Just Drinking Water

Chameleon drinking water droplets from leaves

Unlike most pets, chameleons don’t drink from their cute water bowls. They drink water by licking water droplets and dew off the leaves. In the wild, chameleons will get to drink water only in the early morning and evening when dew is formed on the leaves from condensation.   

In captivity, you mimic this environment by misting your chameleon’s enclosure at least twice a day (at least for 5 minutes). This triggers your chameleon to open their mouths to drink. You will also see the chameleon bringing its tongue forward to drink the tiny water droplets. 

So if you notice your chameleon puffing up and opening its mouth after misting its enclosure, it’s healthy and expected behavior. It is temporary and the chameleon should go back to normal after quenching its thirst. You can use a drinking water fountain like this to provide a continuous supply of fresh, clean, aerated drinking water for your pet.

Reason #3 – Your Chameleon is Shedding Its Skin

Chameleon shedding its skin

As chameleons grow, it is natural for them to shed skin every 4 to 8 weeks. Shedding also helps them keep their skin clean and free from parasites. 

But it is a time-taking process that lasts for a week or more. It is also a very uncomfortable experience for your chameleon with the skin around its eyes and mouth being the hardest to shed. These are the sensitive areas they can’t rub against any surface for relief. So they open their mouths to stretch the skin and make it shed faster. 

Another reason for opening their mouth during shedding can be the irritation they feel which makes them stressed. This is temporary behavior and should disappear once the shedding is complete. 

To make it easier for your chameleon, you can take a damp paper towel and rub it gently around its mouth and nose. This will slowly peel the old skin off their body. You might have to repeat the process several times for this to work. 

Editor’s Note
Remember to never peel the old skin by pulling with your bare hands- it will hurt them if it’s still attached to their body.

Reason #4 – Your Chameleon is Showing Aggression

Green Chameleon with mouth open showing aggression

Chameleons are known for being solitary creatures that prefer to live alone. However, when they do encounter other chameleons, they may display aggressive behavior. One way that chameleons show their aggression is by puffing up and opening their mouths wide. This is often accompanied by hissing, changing skin color, or coiling of the tail. This behavior is a warning to other chameleons to stay away. This is especially true for male chameleons. 

If you handle your chameleon too often, it can feel threatened and become aggressive. In this aggressive state, your chameleon may even bite you.

In captivity, your chameleon can perceive you, your other pets, loud noises, or any major change in their surroundings as a threat. The best way to fix this is to remove the perceived threat. Then observe your chameleon from a distance. Usually, they go back to being normal and stop gaping once the trigger is removed. This behavior is normal. 

You do not, however, want to see this frequently. This indicates that your chameleon is always stressed and anxious. Chronic stress leads to raised cortisol levels and is quite dangerous. Then you have to work on keeping your chameleon healthy and happy.  Here are a few things to keep in mind while creating a relaxing enclosure for your chameleon.

Reason #5 – Your Chameleon is Too Hot

Chameleons are cold-blooded, so they depend on external sources of heat to regulate their body temperature. By opening their mouths, chameleons can increase the flow of air over their mouth and throat, which helps to cool down their body temperature. 

But it’s important to know what else chameleons do to cool their bodies off. In the wild, chameleons have developed the impulse to ascent higher in the direction of the sun. This behavior remains the same in captivity too. A chameleon will ascend and lie down on an exposed branch to warm up. Similarly, it will descend and seek dark areas to cool off.

When you notice this behavior along with gaping, it’s an indication that your chameleon is trying to thermoregulate. In this situation, keep an eye on things, but don’t stand by for too long.

Heat stress can happen if your chameleon cannot cool itself naturally. Thankfully, you can fix this by using some common sense. If your chameleon is exposed to sunlight, bring it indoors. Make the enclosure moist by misting it. You can also place an ice pack outside the enclosure. Then, re-check the ambient temperature inside the enclosure. By taking these measures, your chameleon should feel better soon.

If this is a recurring situation, it’s time to re-evaluate the enclosure environment for ambient and basking temperatures.

Chameleon  Species Male Ambient TemperatureMale Basking TemperatureFemale Ambient TemperatureFemale Basking Temperature
Veiled Chameleons (Chamaeleo calyptratus)24-28°C30-32°C23-26°C27-30°C
Panther Chameleons (Furcifer pardalis)24-28°C30-32°C23-26°C28-30°C
Jackson’s Chameleons (Trioceros jacksonii)24-28°C29-31°C23-26°C26-29°C

Reason #6 – Your Chameleon is Injured

Injured Chameleon with mouth open

While not common, injuries can occur in chameleons and result in them holding their mouths open. The most probable causes of an injury are:

  1. Your chameleon has had a fall that has injured its jaw. 
  2. Your chameleon got bitten by other chameleons 
  3. A  feeder insect has damaged your chameleon’s mouth or face.

If you notice an injury to your chameleon’s face or mouth, it is best to consult a veterinarian who may prescribe antibiotics, clean the wound, and offer guidance on how to promote healing at home.

It is often best to avoid an injury than cure it. Ensure that the chameleon’s enclosure is safe and free from any sharp edges.  Be mindful of the size of live insects you feed your chameleon, and when hand-feeding, deliver worms or grubs headfirst to reduce the risk of bites.

Most importantly, do not keep two chameleons in one enclosure. Chameleons are solitary predators and do not like sharing space. They will be very likely chronically stressed if kept together. Here’s all you need to know about keeping chameleons in pairs.

Reason #7 -Your Chameleon Has a Mouth Rot 

Chameleon mouth rot

Mouth rot (also known as stomatitis) is a common and serious illness that can affect most replite pets including chameleons. It is caused by a bacterial infection when a chameleon suffers oral injuries or decaying food trapped between the teeth.

Poor husbandry can also contribute to the likelihood of mouth rot, with factors such as nutritional deficiency, lack of UVB light, chronic stress, and poor hygiene being significant. 

Although mouth gaping is not the main symptom of mouth rot, chameleons with stomatitis are likely to exhibit this behavior due to mucus buildup and pain around the mouth, which can prevent them from closing their mouths effectively. 

Symptoms of mouth rot include: 

  1. A crooked or open-mouth position
  2. Mucus build-up and yellow discharge
  3. Redness and swelling around the mouth,
  4. Dark-colored deposits on the teeth, 
  5. Indifference to drinking and eating, and 
  6. Swelling around the head. 

If diagnosed early, mouth rot can be treated with antibiotics prescribed by a veterinarian, who will also instruct on how to clean the mouth with an appropriate disinfectant like betadine. 

Reason #8 -Your Chameleon Has Upper Respiratory Infection (URI) 

Chameleons that puff up and open their mouths for extended periods may be experiencing health issues, including respiratory infections. When a chameleon has a respiratory infection, it may sit under the basking light and hold its nose up to clear its respiratory passageways.

It may also take deep breaths periodically, and have mucus in its mouth that may drip down. If a chameleon starts to close its eyes after gaping, it is in critical condition and requires immediate veterinary attention. 

When it comes to feeding, chameleons with respiratory infections tend to ignore food, even their favorites, due to the pain in their throat.

Editor’s Note
Fortunately, URIs are uncommon in chameleon pets. They cannot be treated at home, and there are no over-the-counter medications that can help. It is important to seek veterinary care as soon as possible to treat the infection. Waiting too long can be detrimental to the chameleon’s health.

Reason #9 -Your Chameleon Has Metabolic Bone Disease (MBD)

Metabolic Bone Disease (MBD) in chameleons is similar to Rickets in humans. It occurs because of a shortage of calcium and Vitamin D3 in the body.

Due to a lack of calcium, the body prioritizes keeping the organs functioning by using calcium from the bones. This causes bowed elbows, curved spine, improperly working jaw, and ultimately the inability to hold itself up.

When the disease starts affecting the jaw bones, the chameleon’s mouth remains always open. The tongue does not fit inside the mouth and they appear to be gasping for breath all the time.

It is important to consult the vet if you notice this. The vet will stop it from getting worse, but they cannot fix the deformities that have already happened. If your chameleon’s jaw is twisted, it will never close properly again.

MBD is a severe problem that can lead to death in chameleons and they need immediate attention from a vet.

MBD is tough to cure, but its prevention is easy. Make sure your chameleon gets enough calcium and Vitamin D to help with the absorption of calcium. It’s also crucial to let your chameleon get some sunlight (or at least a UVB light).


Do Chameleons Yawn?

Unlike leopard geckos, chameleons don’t yawn to stretch or if they are tired or bored. Instead, they gape in response to a cause like shedding their skin, being thirsty, being defensive, or regulating their body temperature. Keeping their mouth wide open can also be due to a symptom of a more serious condition.

What Serious Medical Conditions Are Related To Gaping In Chameleons?

Gaping in chameleons can be normal behavior or an indicator of a serious underlying condition like jaw injury, upper respiratory infection, stomatitis, or metabolic bone disease. When it’s the case of a serious condition, gaping is often accompanied by other co-symptoms.

What Can Threaten My Pet Chameleon Enough To Start Gaping?

Chameleons are solitary creatures. You should avoid startling them, petting them, or approaching them from above. They also get threatened by other pets you may have. If you have another pet chameleon, never hold them together in one enclosure.


Now you have learned about all possible reasons a chameleon gapes. Think of the gaping as a communication from your chameleon about a change or its needs. Most probably, your chameleon wants to drink water, regulate its temperature, or is just showing anger. So be observant! 

Lastly, don’t hesitate to consult with your veterinarian if your chameleon is sitting with its mouth open and taking a gulp of air all day long. 

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