Why Bearded dragons need UV lighting
It has been scientifically proven that Bearded dragons need ultraviolet (UV) lighting for both physiological and behavioural reasons. They need UV lighting for two main reasons – sight and calcium absorption.
The UV spectrum can further be broken down into UVA and UVB. These are like the upper and lower ends withing this ultraviolet spectrum. There is probably a lot of overlap, but in general it can be explained as follows:
UVA – More for sight
You might recall the light spectrum (or the colours of the rainbow) from school, namely red, orange, yellow, green, blue, indigo, violet. Humans tend to see all these basic colours, but our eyes are not adapted to see the two extremes (very short and very long wavelenghts). Bearded dragons on the other hand CAN see light in the ultraviolet wavelengths. This image from wiseGEEK shows an ultraviolet enhanced photo of a flower (click to enlarge). Much prettier! Although this in a photographed example, this is how Bearded dragons see all the time – IF the flower is lit up with UV.
Why flowers? Well, it’s not about flowers, it’s about Bearded dragon food in general. UV lighting make food appear completely different to Bearded dragons – making it easier to see and probably making it looking more tasty.
UVB – More for calcium absorption
The correct amount of Calcium makes bones nice and strong and plays vital roles in the neurological system. Calcium is a VERY important mineral for Bearded dragons. Physiologically the body needs vitamin D3 to absorb Calcium. Vitamin D3 can be obtained from proper Calcium supplements (reasonable quantities) or from food (very small quantities). The major source of vitamin D3 comes from the production thereof in the skin, which needs UVB.
Also see the Bearded dragon UV lighting article for more information on how expose your Bearded dragon to the correct amount of UVA & UVB.