Text Box: Text Box: Text Box: UVA/UVB Lighting Many times it is assumed that the only thing a reptile needs for survival in captivity is food, water, heat, and shelter. With many reptiles this is the case. This is not so with bearded dragons. Dragons have very special lighting requirements that are often overlooked, causing poor health and shortened life span. Here is a short educational tidbit on proper lighting for bearded dragons. Dragons require 3 different sources of light. A basking heat lamp, UVA and UVB rays. It is very important to have a UVB/UVA light source during the day time. Basically UVB helps activate the vitamin D3 from food intake which in turn helps with calcium absorption. Without UVB exposure dragons are susceptible to Metabolic Bone Disease. This disease is similar to osteoporosis and rickets in humans. What is UVB? Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 400 nm to 10 nm, and energies from 3 eV to 124 eV. It is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet. UV light is found in sunlight and is emitted by electric arcs and specialized lights such as black lights. As an ionization radiation it can cause chemical reactions, and causes many substances to glow or fluoresce. Most people are aware of the effects of UV through the painful condition of sunburn, but the UV spectrum has many other effects, both beneficial and damaging, on human health. http://en.wikipedia.org/wiki/Ultraviolet to learn more about UV. Where does UVB come from? The main source for UVB is the sun. If you were to use sunlight as a UVB source it would have to be unfiltered. A sunlit windowsill would not normally suffice for UVB exposure requirements because there is some filtration through glass and screens. The only other option is to use a fluorescent bulb. What kind of bulbs should be used? Now, not all bulbs are created equal. The average household fluorescent bulbs and those that say natural sunlight or something to that effect will not always be sufficient, simply because these bulbs do not normally have the proper ratio of UVA and UVB output needed. When buying fluorescent bulbs it is recommended to purchase them from respectable reptile product manufacturers. I would recommend staying away from any compact fluorescent bulbs as these have been linked to cases of photo-kerato-conjunctivitis, a potentially serious eye infection. ReptileUV.com has some extensive studies on bulb UV outputs as well as information on the threats of compact bulbs. Mercury Vapor bulbs like the Mega-Ray and T-Rex flood lamps are good ways to go because they are longer lasting and also produce a good amount of heat as well as UV. Bulb life span Another thing to remember when it comes to UVB light sources is that these fluorescent bulbs will eventually lose their UVB spectrum output long before they will lose their ability to produce visible light. Normally the bulbs will need to be replaced at least twice a year. Zilla claims their bulbs will last 12 months or 3500 hours. There is no way to physically tell if a bulb is old and not producing enough of the UVB spectrum of light, unless you have a UV radiometer to measure the UV output. A radiometer can cost you anywhere from $150 to $500 or more. It is strongly recommended that you write the date the bulb was installed on one end of the bulb or on a sticker attached to the light fixture. That way you will know when the bulb is old and needs changed. Beautiful dragons website has very good information on several different UV lighting outputs based on bulb types. There is a chart that shows UV measurements based on length from the light source and age of the bulbs. Beautiful dragons PROJECT: UVB How much exposure is necessary for good health? Bearded dragons along with most other reptiles will know when they have had enough or too little exposure to UV light. That is why it is always a good idea to have a large enough cage and a hiding area for them to retreat to in order for them to self regulate their intake. Always read the instructions that come with the bulbs and pay careful attention to minimum distances required to prevent possible overexposure. Final Note This was written with bearded dragons specifically in mind. Not all reptiles will require the same amount of UVB exposure and some do not require it at all. Also remember that tube type fluorescent bulbs do not generate much heat so you will still need to offer a basking heat lamp as well, unless you use a Mercury Vapor bulb that generates both heat and UVB such as the powersun models. Bulbs of Choice for us are the mercury vapor bulbs: #1 Mega-Ray MVB (Best, but most expensive) #2 T-Rex MVB (Better, and a little more expensive) #3 Powersun MVB (Good and cheaper than others) With the proper lighting your bearded dragon will be much happier, healthier, and even more colorful. When we changed to mercury vapor bulbs we noticed a huge change in their behavior within only a few minutes. Please remember to always research any potential reptile purchase and all its specific husbandry requirements before you buy it.

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