There is always a lot to talk about lighting the vivarium. Used lighting methods are obviously very important to the climate in the tank. This article descibes some of the relevant facts of importance in searching for the right bulbs.
All DIGF related animals are diurnal, but there are differences in the way these animals use sunlight. A Spiney-tailed lizard for instance will receive more sunlight due to it’s natural habitat and act than a Green iguana. Green iguana’s will spend the hotter part of the days in lower bushes to avoid the heat. It is, more or less, possible to facilitate these behaviour in the vivarium.
Light is part of the electromagnetic spectrum. Part of this spectrum is visible as light.
In lighting, we can speak of natural spectrum when the spectrum of the bulb in question has the same properties (spectrum) as natural sunlight filtered by our atmosphere.
The spectrum of sunlight reaching us can be divided in a number of different types of light or radiation.
Ultra Violet light (180nm – 400nm)
UV light can be divided into three types.
- UVC (180nm – 280nm)
- UVB (280nm – 320nm)
- UVA (320nm – 400nm).
We do not dive in to UVC because UVC radiation from the sun will not reach the earth’s surface. Our atmosphere almost completely filters out radiation below 290nm.
- UVB reaches the earth’s surface from 290nm.
- UVA is a little special because
- UVA isn’t visible to the human eye, but visible for reptiles.
Radiation visible for the human eye form pink (400nm) until red (700nm).
Infrared (700nm – 1mm)
Infrared is heat-radiation; a human body for instance radiates Infrared because of its own temperature. Some reptiles have the ability to see Infrared. Rattlesnakes for instance can find their pray in the dark due to this ability.
Over time, a large number of bulbs became available for our hobby; Every type with it’s own spectrum and purpose.
UV bulbs are available in different types; as Fluorescent tubes, Compact Fluorescent lamp and Mercury vapor bulb. These lamps mostly have a usable spectrum from visible light, UVB until UVA.
In most cases heat spots are (halogen) reflector bulbs. Because of the reflector and lens the light is more or less concentrated in one direction. This bundel of light is usable to create a baskingspot for your animal. The spectrum of these bulbs lies in visible light until Infrared.
In most cases Infrared bulbs only radiate Infrared but no visible light. Some Infrared bulbs aren’t even made out of glass but out of ceramic material. Some Infrared bulbs made out of glass produce a visible red glow.
True light lamps.
True light lamps are Fluorescent tubes or Compact Fluorescent lamps. The spectrum of this lamps is very close to the spectrum of natural sunlight. True light lamps have a spectrum from UVB until the beginning of Infrared (see chart). These lamps do not produce a lot of heat. The Infrared portion of this spectrum is barely there so this lamps aren’t meant as a basking spot. The amount of UV radiation from this lamp is also not strong enough to supply your animal with enough UV. These type of lamps is only intended and used as the base for your lighting plan in the vivarium.
While we are keeping animals in captivity we want to create a habitat which is as natural as possible. Sand and rock formations for desert dwellers, branches and a lot of green for inhabitants of more bushy environments. Natural habitat is also applicable for lighting; in the ideal situation your animals are provided with the natural spectrum of light.
The challenge for us is to combine different types of lamps in order to provide light in the most natural way.
A very important issue; natural light will only shine from above! Always try to fix your bulbs so that they shine from top to bottom of your tank.
Of course we are fixing at least one bulb to heat up the baskingspot. In order to reach the desired temperature you can choose a bulb which will produce enough heat. As you read in the previous chapter; the spectrum of a heat bulb is not equal to the spectrum of sunlight and doesn’t produce UV radiation. Because of this only fixing a heat bulb will, in most cases, not be enough.
In order to provide your animals with enough lighting you can fix one or more True light Fluorescent tubes or True light Compact Fluorescent lamps. This base provides the full spectrum of the sun and improves visibility for your animal. These can be of big importance to different types of animals. A lot of reptiles can see UVA radiation. Because of tha fact that this extra “dimension” in color is being used by a lot of animals, normal Fluorescent tubes will not be enough when we want to provide a natural habitat. Some plants or insects carry UVA reflecting material. Through this material reptiles can recognise them. This UVA reflecting material is also worn by some reptiles; Desert iguana’s in heat carry these material on and around femoral pores. This is why it is important to provide UVA through the whole tank and not only under the UV bulb.
The vivarium is now offering a natural base lighting and heat. Besides this you must add another bulb in order to provide the baskingspot with a higher intensity of UV radiation. Reptiles associate light with heat. In nature this light and heat are coming from the sun only. When an animal is basking it will automaticly also receive UV radiation. In the vivarium it would be ideal to provide a baskingspot with both heat and UV radiation. It is becoming still more and more obvious that UV radiation is needed for your animals to stay healty and to produce natural behaviour. It is also proven that the skin must be warm enough to get the proces of producing cholecaliferol at the right level.
There is a number of UV bulbs available to get the job done. These bulbs provide both heat and enough UV radiation to be used for a basking spot.
Animals from hot biotopes like deserts need a very hot baskingspot to stay healthy. These baskingspots need to have a minimum temperature of 130 degrees Fahrenheit. UV bulbs wil almost never produce enough heat to reach these kind of temperatures. In these cases you can use both a heat bulb and a UV bulb aimed at the same basking spot.
When you fix a heat bulb you must obviously mount it at the correct hight in order to reach the desired temperature. When mounting a UV bulb you must also choose the correct hight in order to obtain the amount of UV ratiation of the natural habitat. The amount of UV radiation is measured in mW/cm2. You can measure the amount of radiation with a UV meter. The closer you are to the lamp the higher the amount of radiation will be. It is of importance that you choose the correct distance between bulb and animal.
A lot of animals (including us humans) use radiation 290nm – 315nm (UVB) to produce cholecalciferol in the skin. Cholecalciferol is used by the body in a further process to make it possible to obtain calcium from food. Because of the fact that all DIGF related animals are primairily herbivorous this process is very important for them.
At the moment of writing this article UVB radiation levels of 75mW/cm2 until 250mW/cm2 are know to be a safe margin. It is advisable to mount your UV bulbs so that this amount is available on the baskingspot.
We are convinced that access to UVA radiation works positive for our animals. They seem to be more active and seem to have more of an appitite. It could even be of positive influence to reproduction.
Click here for more information about the importance of UV radiation for reptiles.
When we use the information provided in this article in the vivarium we may speak of a optimal situation nowadays available; There is provided with a base lighting and there are one or more baskingspots with heat and UV radiation. In this way natural sunlight is approached as much as we can.
Always measure the correct temperature at a baskingspot. The baskingspot must provide the animal with heat and UV radiation levels similar to the levels in the natural habitat. The best way to measure the heat on a baskingspot is by using an Infrared meter. Almost every ordinairy temperature meter will show a higher reading because it lies directly under a lightsource.
It is more difficult to measure the amount of UV ratiation. We know that the radiation between 290nm and 315nm (UVB) is very important. That’s why there’s a meter being developed especially for this particular wavelength; the Solartech 6.2.
DIGF can deliver this meter with a special discount.