Reptile lighting is a very important component of any Reptile housing and goes way beyond simple illumination. Although creating a photo period is vital (a photo period recreates a natural day time night time cycle dawn to dusk) the lighting in a vivarium also provides exposure to components of light radiation that are essential to growth and wellbeing.
One component of natural sunlight, UVB, is responsible for stimulating the synthesis of vitamin D3 which, in turn, means that calcium can be absorbed to be used for bone and shell growth. Lack of UVB exposure leads to metabolic bone disease which causes thin bones and shells. As a consequence reptiles can suffer from thin or weakened bone structure, multiple fractures, reduced mobility and death.