Terrarium Size Guidelines
Aside from providing plenty of space for exercise, the enclosure needs to be big enough to facilitate a proper temperature gradient (discussed further below).
- Juvenile bearded dragons (up to 12 inches) can be kept in a 20 gallon long tank, dimensions 30″ x 13″ x 13″.
- Adult bearded dragons should be kept in a 40 gallon breeder tank, dimensions 36″ x 18″ x 18″.
This is the bare minimum, and extra floor space as well as climbing room is always appreciated. In fact, lately there has been a shift in the bearded dragon community to suggest that 75 gallons (48″ x 18″ x 21″) is the ideal minimum size for an adult bearded dragon.
Bearded dragons are desert reptiles, which means they need warmth, dry air, and do not need to be misted. That said, they still need a mesh lid placed over the enclosure to keep the lizards in and other things (other pets, falling objects, etc) out. Mesh lids are also handy for supporting heat lamps.
If you build your own enclosure: You can build it however large and in whatever shape you want! Just make sure that each dragon has at least 5-6 sq. ft. of floor space. If you need to figure out your enclosure’s approximate gallon capacity, here’s a handy calculator: http://www.firsttankguide.net/calculator.php.
A great resource for building is this article: https://beardies.dreamwidth.org/2145.html. They mention everything you need to build a safe enclosure, complete with pictures for reference. If you’re looking for more ideas, I have a Pinterest board you’ll find handy.
Bearded dragons are diurnal, which means that they are active during the day. In other words:
- They must have UVB radiation
- Plenty of bright, white light is needed for energy, appetite, and mental health.
The Zoo Med ReptiSun 10.0 High Output UVB and Arcadia Desert 12% are fluorescent bulbs that don’t produce heat, but provide plenty of good quality UVB for bearded dragons across the length of the terrarium. (and the Arcadia is especially good). An 18″-24″ bulb set in an under-cabinet light fixture (with the plastic bulb cover removed) installed inside the tank and over the basking spot works great.
PRO TIP: UVB radiation is completely or partially blocked by glass, plastic, and wire mesh. Therefore fluorescent UVBs should be installed inside the enclosure to be effective.
Some keepers choose to solve both of the abovementioned needs at once with a Mega-Ray mercury vapor bulb. Mercury vapor bulbs produce extra-strong UVB wavelengths necessary for bearded dragons to build and maintain strong bones. They also produce a lot of heat, so you don’t need an additional heat lamp. Mercury vapor bulbs can’t be housed inside standard dome heat lamps because they get really hot — instead, they should be installed inside a wire cage heat lamp with a ceramic socket.
However, it should be noted that mercury vapor-type bulbs only provide concentrated UVB directly underneath them, neglecting the rest of the terrarium. So these may be better used in conjunction with a fluorescent UVB than on their own.
The ideal lighting arrangement for bearded dragons is to create a UVB gradient: Use a mercury vapor bulb for the basking spot, then install a fluorescent UVB spanning about half of the enclosure’s length next to it.
UVB Replacement schedule
- Mercury vapor bulbs — every 6 months
- T8 fluorescent — every 6 months
- T5 fluorescent — annually
For more accurate monitoring of your bulb’s UVB output, consider investing in a Solarmeter.
UVB IS NOT OPTIONAL FOR BEARDED DRAGONS!
Like all reptiles, bearded dragons need heat to digest and maintain their immune systems. Without it, they get sick and die. Since bearded dragons are basking lizards, they use heat most effectively from an overhead heat source that mimics the sun.
What’s it like in Australia?
Pogona vitticeps is native to east-central Australia. To understand the Central bearded dragon’s needs for heat, let’s look at climatological data from the Australian Government Bureau of Meteorology, collected between 1950-2005:
- Average temperatures between January-March are from 18-21°C minimum and 33-36°C maximum.
- Average temperatures between March-May are from 12-15°C minimum to 24-30°C maximum.
- Average temperatures between May-July are 18-24°C maximum.
- Average temperatures between July-September are 18-24°C maximum.
- Average temperatures between October-December are from 15-18°C minimum and 30-36°C maximum.
According to the Australian Government Bureau of Meteorology, average year-round temperature for this region is 24-30°C, or 75-86°F. This data set suggests that bearded dragons resist average daytime (ambient) temperatures of around 55°F at lowest and 97°F at highest.
Creating the right temperature gradient for your bearded dragon
Since they are cold-blooded, bearded dragons need a temperature gradient in their enclosure in order to be able to regulate their body temperature. Although they can tolerate very high basking temperatures, they need to be able to escape to cooler areas in the enclosure to prevent overheating. For example, if we were looking at an average enclosure from left to right, the highest temperatures should be at the far left, gradually descending to the lowest temperatures on the far right.
- Basking gradient (juvenile) — 105-115°F
- Basking gradient (adult) — 100-110°F
- Ambient — 80-95°F
- Cool — 70-80°F
Referencing the Australian climatological data mentioned previously, it may seem extreme to recommend such high basking temperatures when the highest average temperature is just 97°F, or 36°C. However it’s important to note that the climatological observations are based on air temperature, not surface temperature. Surfaces like rocks and logs tend to collect heat over the course of the day, becoming significantly warmer than the surrounding air (for example — have you ever burned yourself on a seat belt buckle even though the air in your car wasn’t that hot?). Observations of wild P. vitticeps basking behavior agree; they were found comfortably basking even though their body temperatures measured at 120°F (49°C)! According to a study by Jane Melville and James Schulte, active body temperatures in Central Australian agamid lizards correlate closely with surface temperatures.
Additionally, most reptiles benefit from a nightly drop in temperature, which science suggests may actually strengthen their immune system (rather than weaken it, as commonly believed). Provided that daytime temperatures are correct, pet bearded dragons can handle nighttime drops as low as 55°F without ill effect. Without adequate daytime warming, these cool temperatures may induce brumation or illness.
The wattage it will take to accomplish this varies according to room temperature and distance between the lamp and the basking spot, but a 75w halogen floodlight bulb inside a heat lamp with a ceramic socket is a good place to start. If you can get your hands on one, the Arcadia Deep Heat Projector is the best basking bulb on today’s market (but they’re not available in the US yet *cries*).
How do you make sure you’re doing it right?
Many recommend placing digital thermometers on both the hot and cool ends of the terrarium. But that’s not always the most accurate—especially when you have a large, multi-level terrarium. So I recommend using a temperature gun. I got an Etekcity Lasergrip 774 off Amazon, and it’s spectacular. Measures bathwater temperature, terrarium temps, dragon temps, the whole enchilada. Get. One.