What does excessive UVB light do to reptiles?


Hello all,

Let's assume we are talking about reptiles not receiving a D3 supplement. Captive reptiles can suffer from an excess of D3 due to over-supplementation. However, in the wild, reptiles receive D3 from UVB exposure and their food only. My question is, if I were to put a desert uvb bulb (HYPOTHETICALLY) in with a chameleon who otherwise got all his D3 from his food, and otherwise had perfect husbandry, what would be the effect? If you have references that is great.

I am asking this because I'm developing some research questions to send to potential advisors for graduate school.

Thanks, I'm glad it's a good question. I am asking because globally, UVB levels are increasing. It's having an effect on most species of amphibians, mammals, and birds, but when I ask about reptiles, I either hear silence or "it's not a problem" due to their frankly impressive regulatory systems. I find it highly unlikely it doesn't affect them considering everything else is being affected by the increase!

Seems I may have come across a gap in reptile research!

Madagascar UV Index from January to December:

Madagascar (Tananarive) 19°S 12 12 11 9 7 6 6 8 11 11 12 12 - World Health Organization

Effects of Artificial Ultraviolet Light Exposure on Reproductive Success of the Female Panther Chameleon (Furcifer pardalis) in Captivity

The Transmission of Ultraviolet Light through Reptile Skin Shed.

You question will vary from species to species as they all have different levels of tolerance as well as necessity.....

Rainforest Species
Rainforest species such as some types of chameleon naturally avoid any such high exposure. They need UVB, but at much lower levels. Fig. 8. This Globifer's Chameleon seeks out dappled shade Their more sensitive skins manufacture all the vitamin D3 which they need from brief periods of basking early and late in the day, and the diffused and reflected ultraviolet light permeating the rainforest shade. All species of chameleon have different requirements, but authors vary, too, in their recommendations. The one scientific study we are aware of addresses egg hatchability in Panther Chameleons (Furcifer pardalis) and the authors suggest that a low level of UVB (a gradient between 15-33uW/cm² as measured with a Solarmeter 6.2) supplied for 12 hours a day is optimal. High levels are seen to be harmful.14,19 Our experiences are similar to these findings; one of the current authors maintains gradients of up to 30uW/cm² in all his chameleon vivaria.

Not sure if there are any studies that intentionally try and over expose UVB to see what the consequences are. Most studies done are to find optimal exposure.
Ooo, thank you, this is what I was looking for.

Indeed, most studies are looking to find optimal uvb levels rather than "how much is too much". This is due to the pet trade -- we all want healthy reptiles in captivity. However, I am interested in how much UVB exposure is too much in order to see if it could be a factor affecting reptile populations. Although I haven't read the article yet, it looks like it is exactly what I was looking for. Thanks!
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