Unlike 10 years ago, when the knowledge of this subject was minimal, we now know the requirements of most species kept in captivity. In order to provide reptiles the best possible lighting solution Exo Terra has tweaked all spectrums and added several new bulbs based on recent research.
No longer should anyone rely on the old 5.0 and 10.0 UVB principle, as these fictive numbers only vaguely indicate the UVB output of the bulb ranging between 280-320nm.The wavelength that is responsible for vitamin D3 photosynthesis however, ranges from 290 to 310 nm with a peak production at 294nm. The UVB range below 290nm is undesirable, and can even be harmful, while radiation above 310nm destroys vitamin D3. The positive effects of UVB lighting for your reptile also depend on many other factors, such as whether the bulbs are correctly sited, changed regularly and turned on for a sufficient number of hours.
Exo Terra's new lighting range utilizes a unique new rating system.
In just three easy steps, it will help you determine which bulb is right for your animal. First, check your animal’s star rating on the UV index chart below. Secondly, check your existing set-up for the average basking distance. Thirdly, compare the animal rating and bulb positioning height with those featured on the bulb packaging. If these match, you found the right Exo Terra bulb for your reptile!
Click here to consult the UV rating system.
ABOUT ULTRAVIOLET LIGHT
Ultraviolet radiation only counts for about 3% of the solar energy that reaches the Earth’s surface. It is situated in the high energy portion of the electromagnetic spectrum, just beyond visible light.
Ultraviolet radiation is divided into three wavelength groups:
UVA - Long wave ultraviolet A, ranges from 320-400 nm and is significant for reptile vision and wellbeing
UVB - Medium wave ultraviolet B, ranges from 290-320 nm and is required for metabolic processes
UVC - Short wave ultraviolet C, ranges from 180-290 nm and is dangerous to all living organisms
It has been demonstrated that reptiles can see into the ultraviolet range (300-400 nm), especially in the longwave UVA range. It affects the way reptiles see things (Click here for more information).
Ultraviolet B or UVB is an important element of sunlight for reptiles. In the wild, most reptiles synthesize their vitamin D3 from the UVB component of sunlight. Vitamin D3 is essential for the effective metabolism of dietary calcium in reptiles. UVB reacts with the precursor of vitamin D, 7-dehydrocholesterol, in the skin to produce pro-vitamin D3. Depending on heat and the aid of a mechanism in the skin, pro-vitamin D3 is converted into vitamin D3 itself. The liver and kidneys transform vitamin D3 into its active form, a hormone (1,25, hydroxy-vitamin D) that regulates calcium metabolism.
Carnivorous and omnivorous reptiles get a high proportion of their vitamin D3 requirement from their food. However, plants do not contain D3 (cholecalciferol), instead they contain D2 (ergocalciferol), which is far less efficient in calcium metabolism than D3. Insects and invertabrates do not contain any vitamin D3 at all. Herbivorous and insectivorous reptiles are therefore far more dependent upon vitamin D3 synthesis than carnivorous specimens.
If inadequate levels of vitamin D3 are available, the animal will rapidly develop the condition known as Metabolic Bone Disease. In this condition, bone density suffers and various other serious metabolic problems occur. Symptoms include swelling, lethargy, general weakness, tremors and softening of the shell in turtles and tortoises. Next to a UVB light source, adequate levels of calcium must be present in the diet or must be provided by means of dietary supplementation. Juvenile reptiles are most at risk, although adults too can be affected if maintained in a state of deficiency for a long enough period. Egg laying females are also at great risk, due to the extra demands in calcium necessary for egg production. An excess of UVB can cause eye and skin damage, cancer and poor reproduction.
UVB is generally defined as the wavelength range from 290-320nm, but it is the range between 290-305 nm that is most important. Sufficient irradiation within this narrow sub-band of the UVB range is a requirement for the photosynthesis of vitamin D3 in skin. Although radiation below wavelengths of 310 nm promotes photosynthesis of vitamin D3, radiation above 310 nm destroys vitamin D3 that has been already synthesized in skin tissue or obtained nutritionally.
Some species can regulate the exposure to sunlight to protect themselves from the damaging effects of UVB. Season, time of the day and the environmental and body temperature have an influence on the exposure to the Sun and UVB. Many species also have physical adaptations to protect themselves from UVB damage to vital organs like darkly pigmented UVB-absorbing layers in the skin. UVB rays also contribute to a good working immune system and may stimulate psychological health through the production of beta-endorphins.
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