7. The key of providing the best lighting for our reptiles I believe relies on our knowledge in how a specific reptile receives sun light in his microhabitat. With that said, having a UV light directly on shine 12 hours a day and the 6" usual distance, is that even close to ideals?
What can we do, as hobbyist, to be able to correctly measure the proper "light" for our reptiles?
There are a few studies being done right now for a tiny handful of species, but the "unknowns" far outweigh the "known".
Common sense, though, is a powerful ally; as is the knowledge that the reptile himself is extremely aware of his needs and has evolved to seek out the optimal environment from what's made available to him. If he's got the space to move around and plenty of choice between areas of full light, dappled light, and shade, at different times he will choose different parts of the enclosure, as he would select different parts of his territory in the wild.
Here are my suggestions:
1. Research your reptile! Don't even buy a "beginners" reptile like a leopard gecko until you know where they live in the wild, how they behave in the wild, and whether you can re-create something vaguely resembling that landscape, with its places of shelter (trees, branches and leaves? Rocks and caves? Underground tunnels?) And its combination of light and shade, hot and cold, wet and dry.
2. Buy the best equipment you can possibly afford. The cheapest is hardly ever the best when it comes to heating, lighting and measuring devices. I believe proper digital and/or non-contact thermometers, dimming thermostats for heat lamps and quality UV lamps are essential, not optional extras. A UVB meter is very expensive but saves a lot of anxiety; metabolic bone disorder is one of the most common health problems in captive reptiles, but as far as I know, it's unheard of, in the wild.
3. If you know that your species naturally basks in sunlight, make your vivarium large enough to create a small patch of "sunlight" inside.
Sunlight contains UVB, UVA, good visible light and infra-red (heat). You will need more than one type of lamp to supply all this in one zone. You are trying to create a "sunlight gradient" here, with the UV, visible light and heat diminishing steadily with distance from the source; but the "basking zone" needs to be large enough for the whole body of the reptile to fit inside it. Think carefully about its location and provide nearby shelter. Double-check your temperatures both in the basking zone and at the cool end. Overheating is all too easy when creating "sunlight" indoors, mainly because of limited airflow.
4. Visible light levels are very difficult to guess at, because our eyes accommodate so well. Reptile eyes also accommodate; but the light that reaches the reptile brain directly through the skull is important as well. We can't re-create the full brilliance of natural daylight indoor, let alone sunlight. But if your species basks in sunlight, then the basking zone must surely provide intense full-spectrum, white "daylight" - incandescent lamps or metal halides to provide thousands of lux, not just a few hundred lux from a fluorescent lamp, and certainly not a red "infra-red heat lamp"!
Then, open areas in the rest of the vivarium need to be well lit, too. You don't want a "spotlight on a darkened stage" effect; your reptile needs to be able to see everywhere, not just inside the basking zone. This is where good fluorescent "daylight" tubes can be useful, if you don't want any more heat. For lighting really large habitats or whole rooms, wall or ceiling-mounted metal halides high above the enclosures are unbeatable.
4. The sun is overhead during the day; eyes are designed to cope with this. Avoid angling lamps sideways straight into an animal's line of sight. Do you like driving your car straight into the setting sun?
I'm sure you can think of many other useful and sensible ways of improving a reptile habitat. Examples include altering day length with the seasons, if appropriate; simulating dawn and dusk, by timing the lamps with a lower color temperature (more golden, less UV) to come on earlier, and to switch off later, than the blue-white UVB lamps. If you have a much more sophisticated set-up, you can simulate sunrise and sunset even more accurately with dimmers and so forth.
With that said, we keep reptiles successfully, in my opinion, only because these amazing creatures are remarkably well adapted to survive in adversity.
8. Talking about microhabitat, I know that your research (please correct me if I am wrong) deals with measuring UV rays in reptiles’ microhabitat. Is there a specific research that deals with chameleon in their microhabitat that you know of?
There would have been, but it never happened.
Last February, Dr. Gary Ferguson and Bill Love, specifically to record the UVB, visible light and temperature of chameleons in their native habitat, planned a most exciting little research expedition to Madagascar. Unfortunately, not enough participants booked to go on the trip, which was being organized by Bill as one of his "Blue Chameleon Ventures" Madagascan tours. So it didn't go. Perhaps, in the future...
9. So, now that we understand a bit about attributes of light and reptile needs of light, we finally come to our husbandry. So far, do you have any leaning toward certain type of lights? (I know you mentioned about metal halides).
Sunlight is the perfect light source.
I think the seasonal changes in my own reptiles' behaviors are initiated as much by the changes in daylight they see through the windows as by my feeble attempts to change the day length using timers on my lamps. The night drop in temperature also increases in winter, I think this too plays a part, but I lean towards letting them see daylight as much as possible. My friends Andy and Jeanette Beveridge are very experienced with chameleons and put them in outdoor cages (with appropriate shelter) when the weather is right. My bearded dragons enjoy as much outdoor sunlight as they can get.
Indoors, I think Dr. Henry Brames' catchphrase "select and combine" sums up my view very well.
I would always want to combine a bright lamp with a continuous spectrum (such as a tungsten or halogen incandescent lamp - predominantly light from the red and yellow end of the spectrum, with much less blue and UVA) with a UVB lamp designed for reptiles, which provide UVB, some UVA and a discontinuous spectrum which does however have peaks in blue, purple and UVA.
The sort I would choose would depend on the species and on the vivarium size. My leopard geckos, for example, have small 2ft - 3ft vivaria equipped with household 40W incandescent lamps on dimming thermostats and UVB fluorescent tubes with good UVB spectra but relatively low output (such as ZooMed Reptisun 5.0, Arcadia D3 Reptile, Sylvania Reptistar). My bearded dragons have larger vivaria (4ft+) and these utilise 80W PAR38 incandescent flood lamps combined with flood-type mercury vapour lamps with high UVB output (such as ReptileUV MegaRay and T-Rex Active UV Heat Flood)
But recently, I have been testing some of the new metal halides which emit UVB, and yes, I am impressed. At the moment I'm using them in 4ft vivaria with my chuckwallas and my little Ctenosaur palearis, and I think eventually I might use them instead of the mercury vapour lamps, for all the sun-loving species.
To be continued to Part IV--------------