Sunlight and artificial lighting have 3 wavelengths: UVA, UVB, and UVC.
UVA is the visible wavelength of light, and in reptiles is responsible for inducing "normal behavior" such as feeding, climbing, mating, etc. In other words, it is responsible for the "physiological well being" of reptiles. Zoos have experimented with UVA bulbs for years (ie: BLB blacklights) and found that exposure to high levels of UVA lighting for 2 hours daily induced mating in many species of lizards.
UVB is the non-visible wavelength. UVB in humans is what gives us a suntan. In reptiles UVB facilitates the synthesis of vitamin D3, which allows reptiles to process calcium in their systems thus preventing or reversing metabolic bone diseases.
UVC is the wavelength used for Ultraviolet Sterilizers, which kill harmful bacteria. This wavelength is very dangerous to all animals because it can damage DNA.
Read More > >