Is your bearded dragons mouth open and staying open? What could this mean? Well, it can mean a whole bunch of different things…
Bearded dragons (like humans) yawn at times during the day, normally in the mornings when the lights come on. This will normally only last only a few seconds and is nothing to worry about. They yawn by puffing out their beards a couple times and opening and closing their mouths.
Venting to Control Body Temperature
Often, you will see bearded dragons mouth open when they are basking. The most common reason for an open mouth is to regulate their body temperature. Unlike people, bearded dragons cannot sweat, therefore to control their body temperature, they will open their mouth when they reach their ideal body temperature. Usually, you will see your bearded dragons mouth open while basking under the heat lamp.
Heat exhaustion could be another reason for an open mouth. If you see that your bearded dragon has its mouth open (just breathing), while not basking, this probably indicates that the ambient temperatures are too hot. This is why you should have two sides in your enclosure, a hot side (to bask) and a cool side (to cool down). Having the entire enclosure warm/hot, can be a serious matter for your bearded dragon and can be deadly at times.
Open Mouth Threat
The last reason why a bearded dragon might have its mouth open is to threaten something. This can be another bearded dragon, person, or etc… Usually, an untamed bearded dragon will show this sign when trying to be handled. Because the bearded dragon is unfamiliar with your hand movements, it may try to threaten you by puffing its beard and opening its mouth at you (to seem larger). If you see this happening, it might be best to leave your bearded dragon alone for a while.