Time for a Change
Here at Arcadia Reptile we decided to re-write the lighting advice that was being given. We used science when doing so rather than generalisations. Now, keepers are able to use the published outputs of lamps to re-create the UV levels (UVI) of species in the wild. We studied the wild UVI in the environments of common species and we looked at the habitats of popular species with the aim of understanding how each species used solar energy. We looked at skin thickness in each species and checked this with tetrachromacy (the reptile’s ability to see UV light), aiming to find how much light would be available per species in the wild. We also discovered what is now known as leaf or rock scatter illumination. These are the terms used to describe light that travels down from the forest canopy or passes through holes and gaps in rocks. This means that those species which were traditionally classed as low light requiring species, in fact are now known to use UV levels efficiently.
For example, golden mantella frogs may have been traditionally kept with a 2% T8 UV tube as standard. However reports of their behaviour in the wild show that they often use sunspots created by breaks in the forest canopy which have quite high levels of heat and UV. As such we would now suggest using a higher powered lamp in conjunction with heavy planting to allow this dappled light effect.
The Light Guide
It is essential your reptile is under the correct amount of UV light, this lighting guide will show you how to fit your UV system correctly. We have based the UVI measurements on independent measurements of our UVB fluorescent lamps using a SolarMeter 6.5. This measures the part of the light that is used by animals for vitamin D3 production.
This Lighting Guide shows a suggested basking Ultraviolet index (UVI) per species for different distances from the lamp to the animal’s head. In order to work out these values we looked at the available index of the home range (the species’ wild geographical area) using data from weather stations around the world at 11am. We then reduced this index to allow for cloud cover and further reduced it depending on the animal’s position within the environment and their basking behaviour, i.e whether they are shadedwellers or full sun baskers. We then give a recommendation for the type and strength of lamp to achieve this UVI. This will allow you to create a system in which the animal can choose to allow itself exposure under the light, whilst also being able to move away from direct exposure. This is the basis of the light and shade method.
As example, leopard geckos are from Afghanistan where the UVI often reaches 6. However, leopard geckos are crepuscular – mainly being active during low levels of sunlight. In addition, they will usually bask by only exposing parts of their body. It has also been shown that the leopard gecko has evolved a skin that is particularly effective at absorbing UV-B during these times. Therefore we need to be careful that they do not become overexposed. We recommend providing a UVI of 2 to 3 over the basking zone, down to 0 at the cool end.
All recommendations are based on lamp used with a suitable reflector, fitted on the inside of an enclosure. We have covered around 140 species of reptile, amphibian and invertebrate and will be updating and adding to it over time.