Humidity Levels and Adjusting
The humidity levels of the micro-climate provided to the pet bearded dragon is often overlooked, yet it can have a major impact on their health and well being.
The geographical distribution of each of the Pogona species varies and along with that variation of territory comes different climatic conditions. The following information concentrates primarily on the Pogona Vitticeps being the species most commonly kept in captivity around the world.
In the wild the Pogona vitticeps lives in annual relative humidity of between 20 to 40% (Australian Government Bureau of Meteorology, Relative Annual Humidity, 3pm). This of course fluctuates within the seasons and time of day.
To meet natural conditions and maintain humidity within safe levels, the general recommendation for the captive environment is between 30-40%.
Humidity is measured by a hygrometer. Small enclosures will provide very little, if any, variation on humidity and therefore the hygrometer can be placed in the middle of the enclosure to measure humidity. Large enclosures will allow for a humidity gradient, where this is the case a hygrometer at either end of the enclosure may be beneficial.
Small fluctuations of humidity during the day or at times during the year, for example within 10% of the required levels, should not cause any health concerns. However, this will also be influenced by any pre-existing conditions such as fungal infections. During shedding, humidity should be kept at the top range (40%) to assist.
Humidity is considered high when it exceeds the recommended level of 40%. Excess humidity promotes rapid growth of bacteria and fungus which can reach levels that exceed the resistance of the immune system. This can be exaggerated by using glass enclosures and others that do not have a good level of air circulation. It can cause or contribute to health issues such as:
- Mycotic disease; and
- Respiratory diseases.
Reducing humidity can be a little more challenging than increasing if the excess humidity is caused by the natural climate and not by means under the control of the reptile owner. Glass and small enclosures will present difficulties in reducing humidity. Methods to reduce humidity include:
- Increase the air flow by placing a small fan on a low setting blowing through the enclosure but ensuring it does not blow across the water bowl which could distribute further moisture in the environment or on the enclosure occupant where it may cause irritation.
- Keeping the water bowl is in the coolest area of the enclosure.
- Remove live plants if any.
- Place rice mixed with a small quantity of rock salt into a sock, tie it securely and place it in the enclosure. Replace frequently. This will assist in absorbing excess moisture.
Humidity is considered too low when it is under the recommended level of 30%. The greatest concern for low humidity is dehydration but there are many other issues it can cause including difficulty in shedding. During brumation, humidity levels are particularly important since the lizards can easily become dehydrated during this time and may not wake to remedy the issue. In the wild they will dig into the earth where they naturally maintain their hydration levels. Some of the conditions low humidity or resulting dehydration is known to cause or contribute to are:
- Non-obstructive Dystocia (eggs cannot be passed);
- Dysecdysis (difficulty in shedding); and
- Renal disease.
Humidity can be increased by:
- Misting or soaking branches and placing under the heat lamp. Ensuring their placement does not allow the bearded dragon to access any heat source. Similarly a cloth can be soaked and placed in the basking area providing additional humidity.
- Providing live plants, broad leaved plants contribute well to humidity.
utilising equipment such as vaporizers to increase humidity, however if its placement must be in the enclosure, care must be taken to ensure that the bearded dragon does not have access to the steam where it can be burnt. Consideration must also be given to the electric cord placement.