Every living creature needs water, even the ones that live in arid desert environments. Water is available in three main ways:
Although it’s good practice to keep a shallow water dish in your bearded dragon’s enclosure, bearded dragons get most of their water from their food and from the air that they breathe. Yes, you read that correctly — they can get water from the air. Granted, it’s not very much water. But this small amount of water from ambient humidity helps keep their lungs, skin, and scales healthy.
A common misconception about bearded dragon husbandry is that humidity should be as low as possible, and any instances of relatively high humidity put the dragon in immediate danger of illness. People who perpetuate this myth forget that Central Australia is not bone dry, and it does rain, and humidity does rise occasionally. It’s also important to note that the average human home significantly drier than outdoors, and sometimes too dry, especially if you live in an area with a naturally dry climate. (Fun fact: the ideal indoor humidity for humans is 40-45%.)
The ambient humidity in your bearded dragon’s enclosure should average between 30-60%. You can measure this using a digital probe hygrometer like the Zoo Med Digital Combo Thermometer and Humidity Gauge, with the humidity probe placed on the cool end of the enclosure. Lower or higher than that, and your beardie may start to develop respiratory problems. It may also cause problems with the skin and scales, especially if the substrate is frequently wet. However, occasional brief spikes in humidity due to watering plants in the enclosure, rainy weather, or nighttime is perfectly natural and safe.
Heat and humidity have an inverse relationship. Where it’s hot (such as your basking area), humidity will be low — potentially as low as 10%. Where it’s cool, humidity will be higher. This gradient of temperatures and humidity, as long as they are within correct parameters, will be beneficial, not harmful.