Reptile & Amphibian Forums

Is it possible for your bearded dragons to have to much uvb light ?

Yes though with most UVB lighting available on the market, very unlikely to be a concern with indoor cages. Providing shaded areas or hides in the warm end will allow dragons to get out of direct light while still being able to keep their body temperatures in the range they wish.

Problems in dragons and other reptiles from UVB lights is more due to either mounting Mercury Vabour Bulbs too close to the basking area (these should be mounted at least 18" above the basking area...further away if no screen is between the bulb and the light) and older styles of compact florescent UVB bulbs. What actually causes the problems (conjuntivitus? (not completely sure on the spelling... but more info on the condition and how compact UVB bulbs cause it can be found here: www.uvguide.co.uk/phototherapyphosphor.htm ) is exposure to a high UV index. Not sure about other areas of the world but where I live during the summer (I live in Canada, so we only really have this problem in the summer when its very hot and humid) nearly every hot day (over 75F) the weatherman warns about high UV index ratings and recommends limiting exposure to the sun using sunblock or staying indoors. The higher the UV index rating is, the more dangerous it is to skin...also what causes skin cancer etc. THis is what causes problems in lizards...though not sure if they even get skin cancer, but they do get irritation and damage to their eyes.

Most straight florescent tubes would have to be less than 6" from your dragon to put them into a high UV index. The MVB's is around 15 or 16" hence why its recommended to keep them above 18" (this is the top of the dragon's back when he's on the basking spot...) There is far more details about this at the UVB site I linked above. Its definitely a site worth reading completely, and not just the article about the dangers of some compact bulbs. (use the navigation bar on the left to go to other useful pages at the site).

If you are planning or currently housing dragons in an outdoor enclosure, they certainly can get too much UVB exposure though most likely heat will kill them first. Make sure all outdoor enclosures provide ample hides and shelters for your dragon to get out of the sun when he needs to. If they get too hot they will move into the shade and a shady areas has far less UVB exposure than direct sunlight. Also never leave a glass tank outside in direct sun, it will cook your dragon in a very short time, minutes even, if the sun is strong enough.
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PHLdyPayne