Complete Guide to Humidity Levels
The best humidity level for bearded dragonsThe School of Veterinary Science UQ VETS Small Animal Hospital recommends 30-40%3. In this article, whenever the ideal humidity level is referred, 30-40% is what it means. But is it really that simple? After all, this is covering all species in all seasons whether it is day or night, summer or winter. On top of that, we are using relative humidity, which we will go into in a minute. The great news is that bearded dragons don’t actually need a lot of humidity and it is far better to err on the side of low humidity than high. To see what sort of humidity levels the bearded dragon experiences in its natural environment go to the end of this article – humidity levels for Pogona (vitticeps, barbata, minor, etc).
For Australian KeepersFor those who live in Australia, only bearded dragons that naturally live in the state can be kept as pets. So chances are that if the housing you have provided is appropriate, then you will not have to adjust for humidity. However, monitoring is not only still prudent to ensure conditions remain suitable but in some cases, is a requirement of keeping. For example, in Queensland the Code of Practice for Captive Reptile and Amphibian Husbandry requires that keepers monitor the humidity in the enclosure regularly9. Even if it isn’t a requirement of your state, it is just good and responsible practice.
What is relative humidity?Relative humidity is the measure of how much water vapor the air is holding. This is measured by percentage with the maximum level being saturation point which is 100%. The hotter the air, the more water vapor it can hold. So the amount of water vapor in the air is relative to the temperature. A relative humidity of 40% (ideal humidity level for a bearded dragon) means the air holds 40% of the maximum water vapor that it can at that temperature before it would become saturated. “Air with a temperature of 30°C can hold more than three times as much water vapour as air at 10°C.” Commonwealth of Australia , Bureau of Meteorology
Setting-up to measure humidityEstablishing the point to measure humidity is important to managing humidity levels. This will make the difference between knowing when you need to take action and when not. The probe of the hygrometer must be in a place that is representative of the area you want to measure. Place the probe in a central area. Don’t place the probe in live plant foliage (artificial plant foliage is fine), in corners where air circulation might be limited or over a water dish, as these are likely to exaggerate the level of water vapor in the air giving a reading that is not accurately reflect the environment. Since we know that relative humidity is relative to the temperature, you can see that a reading in a temperature gradient with a range of around 20°C difference from one end to the other can make a huge difference to the reading we get. Assuming the housing heating and lighting has been set up correctly, just place the probe centrally on the back wall and do not put too much emphasis on the humidity. The key here is to ensure the environment is not too moist. Lower humidity levels are fine and conditions often related to it are managed by ensuring good hydration levels are maintained. In other word, let them drink. Be aware that for safety sake, the probe should not dangle down from the housing cover to tempt a curious bearded dragon into checking out the big black bug just waiting to be snapped up and eaten. Place against the wall should be effective for the majority of environments. Having an additional hygrometer outside of the housing will help compare both the internal and external humidity levels making it easier to know which environment needs to be adjusted.
Which Hygrometers to UseSince we are working with relative humidity, having a hygrometer with a thermometer is useful because we know that temperature impacts the humidity reading. So seeing the temperature the hygrometer is recording will make it easier to assess the reading.
It is very useful to have a hygrometer with a probe. This allows you to place the probe wherever it is best situated while the interface can be located wherever it is easiest for you to monitor. Something like the hygrometer shown below will do both.
What you Need to Know to Control Humidity LevelsWe know that humidity is all about the level of water vapor in the air. So it makes sense that to control humidity, you need to be able to adjust the amount of water vapor in the air. Water vapor is added to the air through evaporation and transpiration and removed by condensation or freezing. If the humidity levels are wrong, then look at where evaporation or transpiration is occuring. Before delving into adjusting the bearded dragons habitat, check the room the bearded dragon is housed in. It might be that your climate is humid, in which case that is where the focus needs to be. If it isn’t the wider environment, then investigate the animals housing.
- To control Evaporation: Move any water sources away from heat. If the humidity remains high, try removing the water altogether.
- To control Transpiration: Move any live plants to another room.
Changing Humidity LevelsLow humidity levels are relatively easy to increase, but unlikely needed. Hydration levels of the bearded dragon are far more important than low humidity levels of the environment, so ensure your bearded dragon is getting fluids by mouth. This is very easy to do through vegetation and misting. Try the article on teaching your bearded dragon to drink for more ideas. Keep in mind that the room the enclosure is in is likely to directly affect the microenvironment. It might be that adjusting the room will resolve issues in humidity in the enclosure. Measure both the room and enclosure with a hygrometer to identify which one needs adjusting to resolve any humidity issues quickly. To increase humidity simply add more water to the environment. However, as previously said, hydration levels are far more important than low humidity for bearded dragons. Having said that, you can increase humidity levels by one or more of the following:
- Add a water dish (Be mindful of hygiene and water levels to prevent drowning).
- Misting or soaking branches and placing near the heat lamp (clearly you need to be wary of placement and possible hazards such as fire).
- Adding plants, especially broad leaf plants will help. Ensure the plants are suitable for the occupant of the environment.
- Keeping the water bowl in the coolest area of the enclosure or remove altogether and check if it is reducing the humidity level.
- Remove live plants.
- Use a dehumidifier. Which is suitable depends on how much work the unit must do (area of room and humidity level). This is going to be the quickest and easiest way to fix the issue.
Choosing a DehumidifierA dehumidifier will provide a reasonable solution for excessive humidity. The desiccant and refrigerant dehumidifiers are reasonable options. It is unlikely you will need a dehumidifier running all the time. Your aim is not to totally dry out the environment, simply bring it within the 30-40% range. The desiccant dehumidifiers range from small units which can easily be added to any environment, to large ones suitable for rooms. The [amazon_textlink asin=’B000H0XFCS’ text=’Eva Dry (available here on Amazon)’ template=’ProductLink’ store=’melville1-20′ marketplace=’US’ link_id=’3d3c0d11-fb5f-11e7-b954-cdd0605d208b’] is perfect for small areas (only 14 cm high), it is non-toxic (pet and child safe), can work for up to 10 years (I wouldn’t count on that) and doesn’t require power making it easy to pop it whenever you need it, whenever you need it. How it works is it has a renewable silica gel that absorbs moisture. Somewhere between 3-8 weeks the gel goes to its full capacity point and needs to dry out so it can remain effective. The gel changes color to indicate when it needs you to plug it in for a day to bring the crystals back to usable state. Although by rights you could put this in the enclosure (it is pet friendly) I would really recommend you don’t. There is potential for this to dry out the environment too much and becomes another object that needs to go through the habitat cleaning program which is not going to be easy on a device like this. Try experimenting with it outside of the enclosure. Majority of feedback is that they work well as specified and people are happy. But a few people have reported them being totally unsatisfactory and either doing nothing or having to dry out the gel every couple of days. It is unclear what conditions the unit was subjected to in these cases. Given the majority of feedback on them is positive and that they are so low cost, it is well worth a try to lower humidity for your bearded dragon housing before moving on to other options. There two sizes for Eva Dry portable gel technology range are the E333 (pictured) and the E500. The model refers to the cubic feet it will cover. So the E333 covers 333 cubic feet and the E500 covers 500 cubic feet. From there you can go into refrigerant dehumidifiers. The [amazon_textlink asin=’B01IFOTM2Y’ text=’Comforday Compact Dehumidifier’ template=’ProductLink’ store=’melville1-20′ marketplace=’US’ link_id=’9c7951d2-fb88-11e7-b9d9-1b179a6f03f1′] has received hundreds of good reviews and is about the cheapest you are going to get at under $50 US. Although it has had a lot of good reviews it has also had a few poor ones so check those out as well. At the time of writing this it had a 4.3 out of 5 star rating which is pretty good. Some of the more expensive units can get closer to 5 stars if you want a bigger and longer lasting solution. The reservoir is very small and it isn’t really made to last the long haul, but it is cheap and shouldn’t really be doing that much work. If it is working too hard then the environment is really unlikely to be suitable to keep a bearded dragon. The dehumidifier shouldn’t have to be working more than part-time. [amazon_textlink asin=’B073VBWKJZ’ text=’HomeLabs has a bigger 9 gallon dehumidifier’ template=’ProductLink’ store=’melville1-20′ marketplace=’US’ link_id=’3c169fba-fb8f-11e7-b254-3f36c21c9c99′] designed for large rooms. It has 4.7 stars at the time of writing and that is with over 1000 reviews. It is 5 times the cost of the Comfortday but it is a longer term option. Neither of these dehumidifiers are suitable for putting in the enclosure. Not only because of potential danger to the animal but also because it is likely to dry things out too much. Plus the HomeLabs dehumidifier unit is bigger than some of the enclosures! Keep it outside of the enclosure and experiment with its location, monitoring the humidity levels with your hygrometers.
Health Issues Caused by the Wrong Humidity LevelsThe greatest immediate health concern for low humidity for bearded dragons is dehydration. Serious dehydration is not the only threat, constant mild dehydration can cause deadly health issues. Health problems which may be contributed to by low humidity are also ones that are attributable to dehydration. In other words, it is far better to provide a proper hydration routine and err on the side of low humidity than to have high humidity. Any bearded dragon suffering from the following are unlikely to have been provided sufficient fluids by mouth and no amount of humidity that is safe would save that.
- Avascular necrosis (juvenile Bearded Dragons are more susceptible)1
- Dysecdysis (difficulty in shedding)1, 3
- Renal disease2, 5
- Non-obstructive Dystocia (eggs cannot be passed)4
- Urinary tract disease5
- Bacterial infections6
- Ulcerative or Necrotic Dermatitis7
- Mycotic disease7
- Respiratory diseases8.
Humidity Levels in the Bearded Dragons Natural EnvironmentThe range of natural environments bearded dragons can live in is huge. The geographical distribution of each of the Pogona species varies. Along with that variation of territory, comes a range of different climatic conditions. Although it is never in cool areas such as Tasmania. However, Tasmanian authorities see bearded dragons as a pest threat and monitor the situation. You can’t legally keep bearded dragons in Tasmania as pets either, that’s how much of a pest threat they are considered there. One woman keeping a bearded dragon certainly found this out when her pet was taken by the police. The map below shows the distribution of bearded dragons (most commonly kept as pets around the world are Pogona vitticeps followed by Pogona barbata). The distribution data is from the Australian Reptile Online Database (AROD) overlaid on a map from the Australian Government Bureau of Meteorology displaying the relative humidity ranges at 9am over a 30 year period (1961-1990). On the map you can see quite a range in humidity levels for bearded dragons. This is great for a general idea but of course in reality, relative humidity goes up and down with temperature. So from one hour to the next, one season to another, the humidity fluctuates. In the map below, the annual average at 9am and at 3pm are shown without the bearded dragon distribution overlay. This shows the humidity from one time in the day to another can range quite significantly. The following map shows the average annual humidity over a 30 year period for Summer in the month of January and a winter month of July at 9am.
- Bearded Dragons – Problems by Rick Axelson, DVM. Care & Wellness, Medical Conditions, Nutrition, Zoonosis and Human Health
- Acute and Chronic Renal Disease: Diagnosis, Treatment, and Prognosis in Lizards by Drs. Foster & Smith Educational Staff adapted from the information presented at the Western Veterinary Conference, 2003
- The School of Veterinary Science UQ VETS Small Animal Hospital (part of the University of Queensland, Australian)
- Preovulatory stasis and dystocia in oviparous lizards. Raffaele Melidone, Dr. med. vet.; Joyce S. Knoll, VMD, PhD, DACVP; and Nicola Parry, BSc, MSc, BVSc, DACVP. Veterinary Medicine. November 2008, 595-598
- Reptile and Amphibian Urinary Tract Medicine: Diagnosis and Therapy. Paul M. Gibbons, DVM, MS, Dipl ABVP (Avian Practice), Animal Emergency Center, Glendale, WI 53066 USA
- Hôpital Vétérinaire Chambly
- Mycotic Diseases of Reptiles by Stephen J. Divers, BVetMed, DZooMed, DACZM, DECZM (herpetology), FRCVS, Professor of Zoological Medicine, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia
- Respiratory Conditions in Reptiles by Sean McCormack BSc (Hons), MVB, MRCVS. 30 December 2015
- Captive reptile and amphibian husbandry. Code of Practice. Wildlife management. Nature Conservation Act 1992. Department of Environment and Heritage Protection