Safe lighting for a bearded dragon
I have a D3+T5 system for my bearded dragon and I wondered if fitting the lamp and reflector 20cm (8in) from the dragon’s back is at all dangerous? Also, are there any other things that I should be concerned about?
As in the case of other lizards, suitable lighting naturally enhances the colouration of a bearded dragon.
Exposure to a UV index that is significantly higher in a vivarium than can be found in nature is not to be recommended in my view. The reptile would not have had an opportunity to develop a use for this index of exposure, or a level of in-built protection against it. This could therefore prove to be dangerous over a period of time.
You should also to be aware of the risks from non-terrestrial wavelengths of light. While UVA and UVB wavelengths are beneficial, UVC is deadly! It is not found in sunlight as the earth’s atmosphere filters it out, but these damaging wavelengths can be projected from an artificial light source.
I can only speak for Arcadia Reptile, but all of our lamps incorporate 100% UVC protection. This particular wavelength will cause skin and eye burns and can lead to skin cancers and has other adverse effects. It is commonly used in hospitals and in pond filtration systems to destroy bacteria or algae, being described as germicidal or sterilising light. Neither your reptile nor you should be directly exposed to this type of UV light.
The vivarium environment
The ‘light and shade method’ simply describes the practice of providing heat and light over a measured and defined section of an enclosure. This then allows the bearded dragon to use its ability to see UV light (which we are unable to do), and adjust its position accordingly within its enclosure, according to its requirements.
Lighting and heating should tie in together. So place the heat source and light at one end therefore, which will then allow a fall-off to cooler, shadier conditions at the other end.
Hides can also be used and will serve to mimic wild patterns of behaviour, which typically involve basking and then hiding away during the heat of the day. Reptiles are commonly found in burrows and under rocks at this stage of the day. This protects them from over-exposure and predation, and in most cases it allows them to find some level of humidity as well.
With older, less powerful lighting technology, the general advice was against the use of hides as the UV systems were underpowered. This meant that we had to encourage an animal to spend longer periods under weaker forms of light, in order to meet its UV needs. With T5 now being so powerful though, this means that we can now mirror the conditions that a reptile would experience in the wild.
Wild bearded dragon sunning itself in Australia.
Positioning the lamp
A well-recognised risk associated with a lighting system where the lamps are poorly fitted is of course eye inflammation and/or infection. All lamps MUST always be fitted to the roof of an enclosure and never hung half way down the back wall.
Light from any source (and not just UV lamps) hitting the eye of an animal from the side can cause inflammation. If left untreated, this can in turn lead on to infection. So all lamps should be fitted well above the top of the vivarium occupants, with suitable reflectors being used.
I would advise fitting lamps in the corner between the roof and the front plate above the door. This ensures that the light is above the lizard and is also out of an onlooker’s direct eye line. Lamps do look ugly, particularly when they loom above attractive naturalistic décor.
You can then use your chosen decoration to generate a useable ‘solar gradient’ within the enclosure. So with the aid of a suitable reflector, a High Output T5 D3+ 12% lamp will be producing suitable levels of exposure at around 30-38cm (12-15in), as measured from the lamp to the lizard’s back at the highest point. I would advise that 20cm (8in) is too close.
Your basking platform could be almost pyramidal in design or a graduated slope with the thin edge entering the cool zone and the highest point under the hot zone, creating an upper index basking zone. This will then allow the lizard to adjust its position in accordance with its needs.
Don’t forget that hydration and measured supplementation, especially with calcium, are all vital in terms of the vitamin D3 cycle as well. This is in addition to the correct lighting. The way that we keep reptiles has changed, and brought measurable benefits. It will undoubtedly continue to so in the future, as our systems become increasingly sophisticated.