A bearded dragon’s mouth open is usually a sign that it is cooling down by releasing excess heat. This is known as gaping and is a vital part of how it regulates its body temperature, but it is only one of many thermoregulating behaviors.
This post explores scientific research examining how bearded dragons adapt their thermoregulatory behavior in diverse temperature environments.
These studies provide critical insights into the necessity of appropriate environmental conditions for bearded dragons, highlighting the practical impact of temperature on their well-being and care. Understanding these behaviors is crucial for pet owners to ensure a healthy and comfortable life for bearded dragons in captivity.
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Key Points
- Your bearded dragon’s mouth open is a critical sign that they are successfully regulating their temperature.
- The temperature threshold for gaping begins at around 36.9°C (98.4°F).
- The environment impacts bearded dragon thermoregulation.
- Adult and baby bearded dragons have different thermoregulatory behaviors, which are learned.
- Bearded dragons have both voluntary vs. involuntary thermoregulation behaviors.
- Gaping helps maintain body temperature.
- Keeping bearded dragons together influences thermoregulation behavior.
- Males or females gape at different temperatures.
- Lighting, temperature, and humidity levels are essential to optimal thermoregulation.
Why is my Bearded Dragon’s Mouth Open?
A bearded dragon’s mouth open (gaping) is just one of the behaviors these reptiles use to thermoregulate. Gaping is a response to high temperatures, helping them cool down through evaporative cooling. You’ll most commonly see this when they are basking under sunlight or a heat lamp, allowing heat to escape through their open mouths.
Bearded dragons are ectothermic (cold-blooded), meaning they rely on external heat sources to regulate their body temperature. Whether they are basking in heat or moving to a cooler spot, these behaviors help them maintain the right balance. When it’s hot, and your bearded dragon’s mouth is open, they are likely cooling down after soaking in the warmth.
Maintaining the right body temperature is vital for their health. Their behaviors—such as gaping, moving between hot and cool areas, or adjusting their position—are critical for supporting key functions like metabolism, digestion, and daily activity.
In the wild, bearded dragons start gaping at specific temperatures. Studies show that gaping usually begins around 36.9°C (98.4°F), a temperature that triggers their thermoregulatory response. This behavior is more than just cooling off—it’s a physical and physiological response that also includes changes in heart rate and blood flow.
Why does a Bearded Dragon Keep Basking if it is Hot?
Bearded dragons don’t always move away from heat, even when they’re too hot. This is because their need for UVB is outweighing their need to reduce their heat. UVB is crucial for their health, helping them synthesize vitamin D, which is essential for calcium absorption and bone health.
Instead of moving away immediately when they get too hot, bearded dragons may rely on behaviors like gaping (keeping their mouth open) to release excess heat. This allows them to stay under the heat source to continue absorbing UVB without overheating.
Why Bearded Dragons Need to Regulate Their Temperature
For bearded dragons, keeping their body temperature stable is crucial for their overall health. This impacts everything from their metabolism to digestion and activity levels. When you see your bearded dragon’s mouth open, they are using a natural method called gaping to release excess heat. Gaping and other responses, like moving between warm and cool areas, helps them maintain a comfortable body temperature.
How Bearded Dragons Respond to Temperature Changes
Bearded dragons have complex responses to temperature fluctuations that are highly dependent on the quality of their environment.
Proper habitat management is key to meeting their thermoregulatory needs. In the wild, the bearded dragon’s mouth opens as part of its temperature regulation strategy, along with other behaviors such as basking, seeking shade, and adjusting its body position in relation to heat sources.
Basking: Bearded dragons move toward a heat source to raise their body temperature. They do this by positioning themselves under direct sunlight or a heat lamp.
Shuttling: Bearded dragons actively move between warmer and cooler areas to balance their temperature. This is a common strategy for maintaining the desired body heat. When they become too warm, they may move into shaded areas, helping to lower their body temperature.
Changing the bodies orientation: When gaping is restricted or the bearded dragon needs more or less heat, it changes its body’s position relative to the heat source. For example, it may turn its head or body toward or away from the heat.
In the wild, if a bearded dragon needs to warm up, it will orient its body perpendicular to the sun’s rays, increasing the surface area exposed to the sun. This boosts heat absorption. Conversely, if they need to cool down, they will orient their body parallel to the sun, reducing heat absorption. Similarly, when a bearded dragon’s mouth is open, they are engaging in a cooling process.
Adjusting Body Posture: Bearded dragons flatten their bodies to absorb more heat when basking. They can also curl or lift parts of their body off the ground to reduce heat absorption when they need to cool down.
Bearded dragons also use their head as primary heat sensors. For instance, if they sense a hot rock, they may turn their head toward it to absorb more heat or away to avoid overheating.
Research by Black and Tattersall (2017) shows that bearded dragons, both young and adult, adjust their positioning relative to heat sources to maintain their preferred body temperature, which is usually around 33°C to 34°C (91°F to 93°F). Adults are more likely to orient directly toward the heat source when it’s cooler, and this behavior gradually decreases as the temperature rises. In contrast, younger bearded dragons may take longer to learn how to regulate their temperature effectively.
Gaping (Mouth Open): The most noticeable of thermoregulation behaviors is gaping, when you see a bearded dragon’s mouth open. Gaping is a cooling mechanism that helps them release heat. Gaping typically occurs at temperatures between 33°C to 35°C (91°F to 95°F).
There are different levels of bearded dragon gaping based on the degree their mouth is open and dependent on how fast they intend to change their body temperature:
- Minimal opening, barely distinguishable from a closed mouth.
- Moderate opening, more than a few millimeters.
- Wide open mouth with visible tongue and expanded throat.
When gaping is not possible, bearded dragons may adjust their orientation or position to manage their heat exposure.
Skin Color Changes: Bearded dragons change the color of their skin to manage heat. Darker skin absorbs more heat, while lighter skin reflects it, helping regulate their body temperature when it gets too hot or cold.
Heart Rate Changes: Research by Seebacher and Franklin (2003) demonstrated that the bearded dragon’s heart rate varies significantly depending on whether they are warming up or cooling down. A bearded dragon’s heart rate increases much more rapidly during the warming process and slows down during cooling. This physiological adjustment is crucial because it allows bearded dragons to speed up or slow down their rate of heat absorption or dissipation.
- During heating, bearded dragons’ heart rates increased by approximately 6.22 beats per minute per degree Celsius.
- During cooling, their heart rates slowed to about 4.61 beats per minute per degree Celsius.
By accelerating their heart rate when they are warming up, bearded dragons can quickly distribute heat throughout their bodies, speeding up the heating process. Conversely, during cooling, a slower heart rate helps retain heat longer, preventing rapid cooling that could disrupt vital bodily functions.
Factors that Influence Thermoregulation Behavior
Age: Differences Between Adults and Baby Bearded Dragons
Adults: Research by Black and Tattersall (2017) shows that adult bearded dragons start adjusting their position toward heat when the temperature falls below their preferred range (below 33°C or 91°F). They often turn their head or body toward the heat source to absorb more warmth. Once they’ve absorbed enough heat, they turn away to avoid overheating. Their fine-tuned behavior allows them to maintain an ideal temperature with minimal effort. You’ll see an adult bearded dragon’s mouth open less frequently once they stabilize their body heat. In addition, they may move away from the source or reorient themselves to prevent overheating.
Babies (hatchlings): Black and Tattersall (2017) also found that this process for baby bearded dragons is similar but less refined. Baby bearded dragons also begin seeking heat when the temperature drops below their comfort zone. However, baby bearded dragons’ behavior is less consistent than that of adults.
For babies, the ability to control their temperature is still developing. They tend to overheat or stay cold for longer because they’re still learning to position themselves correctly in their environment. It takes a few hours of exposure to their surroundings to adjust their orientation toward the heat source effectively. You might notice a baby bearded dragon’s mouth open more frequently in babies as they take time to figure out how to manage their heat exposure.
Even though both adults and babies prefer to keep their body temperature around 33–34°C, babies take longer to adjust their orientation toward the heat source. You may see a baby bearded dragon mouth open more frequently as they are still figuring out how to cool themselves efficiently. Babies are still in the learning phase, taking a little longer to get it right.
The Differences Between Male and Female Gaping
Research by Black and Tattersall (2017) found that gender may play a role in the thermoregulatory behavior of bearded dragons.
Females Like it Hotter: During the thermoregulation process, females preferred temperatures about 1.78°C (3.2°F) higher than males. This could suggest a difference in how each sex regulates body heat, potentially linked to metabolic or reproductive factors.
Females May Prefer to Face the Heat: While both sexes exhibit orientation preferences (facing towards heat sources at lower temperatures and away at higher temperatures), males were 37% less likely to face the heat source than females. However, the researchers concluded that the difference was not statistically significant and may not be a reliable indicator of thermoregulatory differences between the sexes.
Keeping Bearded Dragons Together and the Impact on Thermoregulation
Housing bearded dragons together in a shared environment can influence their thermoregulation. A study by Khan, Richardson, and Tattersall (2010) found that baby bearded dragons housed individually and in groups achieved similar levels of thermoregulation, maintaining their preferred body temperature of around 35°C. However, the bearded dragons housed in groups displayed more variability in their skin temperature and less precision in thermoregulation compared to those kept alone. This may be due to moving more frequently to avoid or compete with cage mates.
In a group setting, you may still observe a bearded dragon with its mouth open as it releases excess heat. Still, there may be more variation in behavior compared to those housed individually. The study revealed that when a light bulb was on, baby bearded dragons oriented their heads toward it to absorb heat and UV light. They moved away once the light was off and positioned themselves randomly, underscoring their reliance on environmental cues for thermoregulation.
The researchers also showed that both baby bearded dragons kept on their own and those kept together were attracted to a light bulb when it was on, regardless of the ambient temperature. This suggests that the light bulb was a valuable resource for the bearded dragons, providing heat and UV light. It is also a good reason not to provide light at night-time.
The researchers concluded that bearded dragons tend to group together around shared resources like heat sources. Still, the increased variability in their thermal preferences could lead to competition or less efficient thermoregulation. When housed together, you might notice differences in how often you see a bearded dragon’s mouth open, reflecting the varied strategies they adopt to manage body temperature in a shared space.
In summary, while bearded dragons in groups can thermoregulate effectively, they exhibit more varied behavior, likely due to the need to share resources like heat and UV light. This can affect how consistently they manage their body temperature compared to dragons housed individually.
How the Environment Impacts Thermoregulation
A good thermal quality environment will make it easy for an animal to maintain its preferred body temperature. Good thermal quality environments significantly impact a bearded dragons’ behavior. A study by Cadena and Tattersall (2009) explored how bearded dragons in high-thermal-quality environments, could regulate their body temperature effectively by moving between warm and cool zones. In low-thermal-quality environments, you may see a bearded dragon’s mouth open more frequently as they work harder to manage their body heat.
Several environmental factors can affect how often and how long you’ll notice a bearded dragon’s mouth open as they thermoregulate:
High temperature increasing gaping time : When the temperature increases, a bearded dragon’s mouth will often open more frequently as it attempts to cool down.
Heat source positioning impacts gaping: If the basking area is too hot or the heat is too close, your bearded dragon may spend more time with its mouth open to compensate.
High humidity increases gaping time: High humidity can reduce the effectiveness of evaporative cooling, leading to prolonged gaping sessions.
Extreme harsh environments force conservation of energy: In challenging conditions, such as extreme heat or cold, bearded dragons might limit or cease their usual thermoregulatory behaviors to conserve energy, and their gaping behavior could become less frequent or stop altogether.
Impact of Starvation and Dehydration on Thermoregulation
Extreme conditions like starvation or dehydration can significantly disrupt a bearded dragon’s ability to regulate their temperature. When dehydrated, a bearded dragon may stop gaping, as they cannot afford to lose more fluids through evaporative cooling. Even if you don’t see your bearded dragon’s mouth open, they may rely on other thermoregulatory strategies like moving to cooler areas or shuttling.
Scarpellini et al. (2015) found that dehydration, simulated by salt loading, reduces gaping and causes a rise in head and body temperatures. The research suggests that bearded dragons conserve water during dehydration by minimizing evaporative cooling, like gaping, but they continue to use other methods of thermoregulation when water is available. Essentially, a dehydrated bearded dragon avoids gaping to conserve fluids, instead opting for behaviors like shuttling between cooler and warmer areas to regulate their body temperature.
This behavior highlights the critical importance of providing proper hydration and environmental conditions. Without adequate water, a bearded dragon’s ability to thermoregulate through gaping is compromised, negatively affecting their health.
What Happens if a Bearded Dragon Cannot Gape
Black, Aedy, and Tattersall (2021) showed that when gaping was prevented, the lizards compensated by orienting their heads toward the heat source. They also moved to a position in their cage at a temperature lower than they preferred. This suggests that bearded dragon gaping is costly, and they prefer a lower temperature than to gape.
Bearded Dragon Panting
Bearded dragon panting is different from gaping. When a bearded dragon pants, it changes the way it breathes. Panting means breathing faster, but each breath isn’t as deep as normal. It’s like taking quick, shallow breaths instead of slow, deep ones.
When a bearded dragon pants, it helps it cool down, especially when it gets really hot. This method is more commonly seen in mammals like dogs as a response to intense heat stress when they are trying to cool off.
7 Steps to Creating the Best Environment for Bearded Dragon Thermoregulation
To support your bearded dragon’s thermoregulatory needs, you need to create an environment that allows for effective bearded dragon gaping and other behaviors:
Step 1. Setup a temperature gradient: Instead of a uniform temperature, provide a thermal gradient in the enclosure. This allows your bearded dragon to move between warmer and cooler areas to find the most comfortable spot for regulating their body temperature.
Step 2. Avoid extreme temperatures: Protect your reptile from extreme or sudden temperature changes. Using thermostats and timers is crucial to stabilize the environment and prevent stress and dysfunction.
Install proper lighting and heating with a thermostat and timer. Heat and UVB lighting are essential for your bearded dragon’s health and thermoregulation.
Step 3. Maintain appropriate humidity: It is important to keep humidity levels around 30–40% to ensure your bearded dragon’s mouth-open behavior (gaping) works as it should. Proper humidity levels also aid in cooling.
Step 4. Monitor their behavior: Watch for signs of overheating, such as when you notice your bearded dragon’s mouth open for prolonged periods. Regularly check temperature and humidity levels using thermometers and hygrometers to ensure the environment is within a safe range.
Step 5. Monitor their environment: Use thermometers and hygrometers to monitor your bearded dragon’s environment, ensuring they remain within a safe and comfortable range.
Step 6. Manage Hydration: Always provide fresh water. Hydration supports your bearded dragon’s overall health and helps prevent overheating.
Step 7. Housing Bearded Dragons Together: While housing young bearded dragons together may offer benefits like shared heat and UV light, it can also lead to competition and stress. Provide ample space and hiding spots to mitigate potential conflicts.
Conclusion: Mastering Bearded Dragon Thermoregulation
Thermoregulation is a complex set of behaviors from your bearded dragon’s mouth open to a change in heart rate. Creating the right environment and closely monitoring their habits can ensure your pet stays healthy and comfortable.
Because bearded dragons rely on their environment for thermoregulation maintain a well-equipped habitat with heat lamps, thermostats, timers, hygrometers, thermometers. Properly set up basking and cooler zones are essential.
Seeing your bearded dragon’s mouth open is the most obvious sign that it is regulating its temperature. However, if you notice unusual or excessive gaping, it could be time to reassess its habitat to ensure it lives in optimal conditions.
FAQ’s
Why is my bearded dragon’s mouth open?
If you see your bearded dragon’s mouth open, it’s usually because they’re gaping to cool down. This is normal during basking and helps them release excess heat. If gaping happens when they aren’t basking, it could be a sign of stress or illness.
Why is my bearded dragon gaping?
Gaping helps your bearded dragon regulate heat and improve air circulation, especially during basking. If your dragon gapes frequently when not basking, monitor for signs of stress or respiratory issues.
What if my bearded dragon is gaping outside of basking?
Frequent gaping when not basking could signal stress, respiratory issues, or problems with their habitat. Check the temperature and humidity, and ensure they can access warm and cool areas.
Why is my bearded dragon panting?
Panting typically means your bearded dragon is trying to cool down. If they’re panting excessively, check for overheating or signs of stress. It may also point to a respiratory issue.
Why is my bearded dragon pancaking?
“Pancaking,” when your dragon flattens against a surface, is usually done to absorb more heat while basking. It can also be a defensive behavior, making them appear larger if they feel threatened.
References
Black, I. R. G., & Tattersall, G. J. (2017). Thermoregulatory behavior and orientation preference in bearded dragons. Journal of Thermal Biology, 69, 171–177.
Cadena, V., & Tattersall, Glenn J. (2009). The Effect of Thermal Quality on the Thermoregulatory Behavior of the Bearded Dragon Pogona vitticeps: Influences of Methodological Assessment. Physiological and Biochemical Zoology, 82(3), 203–217.
da Silveira Scarpellini, C., Bicego, K. C., & Tattersall, G. J. (2015). Thermoregulatory consequences of salt loading in the lizard Pogona vitticeps. Journal of Experimental Biology, 218(8), 1166–1174.
Khan, J. J., Richardson, J. M. L., & Tattersall, G. J. (2010). Thermoregulation and aggregation in neonatal bearded dragons (Pogona vitticeps). Physiology & Behavior, 100(2), 180–186.
Seebacher, F., & Franklin, C. E. (2003). Prostaglandins are important in thermoregulation of a reptile (Pogona vitticeps). Proceedings of the Royal Society of London. Series B: Biological Sciences, 270(suppl_1).
Seebacher, F., & Franklin, C. E. (2005). Physiological mechanisms of thermoregulation in reptiles: a review. Journal of Comparative Physiology B, 175(8), 533–541.
Tattersall, G. J. (2005). Hypoxia progressively lowers thermal gaping thresholds in bearded dragons, Pogona vitticeps. Journal of Experimental Biology, 208(17), 3321–3330.
