Sunlight and Artificial Sunlight

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Captive reptiles rarely receive adequate exposure to ultraviolet

(UV) light, especially when they are housed indoors.  Captive

reptiles, especially iguanas, must receive direct sunlight to

benefit from its UV component.  Ultraviolet light is necessary to

properly absorb dietary calcium.



Window glass and plastics filter UV light.  Consequently,

reptiles must be housed in screened or wire enclosures during the

time they are to be exposed to direct sunlight.  Also, a shaded

area must be provided so the iguana can avoid heat stroke from

overexposure to sunlight.



An alternative to direct sunlight for reptiles housed indoors is

an artificial UV light source, such as a Vitalite (Duro-Lite

Lamps, Lyndhurst, NJ  07071).  To approximate a natural

photoperiod, it is best to supply 10-12 hours of daylight and

12-14 hours of darkness each day, with a gradual increase in the

number of hours of light supplied in the spring and a gradual

decrease in the number of hours provided in the fall and winter

months.