Care in Captivity Green iguanas are tropical animals. A captive environment should be set up to best approximate the temperature, humidity, and ultraviolet light found in the reptile's natural settings. Ultraviolet light Access to ultraviolet light is one of the captive iguana's most important requirements. When the sun's rays hit the iguana, Vitamin D is manufactured by the body. This vitamin is essential for proper absorption and utilization of calcium by your iguana.
Calcium deficiency is the most common medical problem seen in captive iguanas.
The best source of ultraviolet light is the sun. In northern climates, the sun is strong enough to be beneficial only in the summer. It is not known how much sun is enough, but iguanas should receive a full day of sun at least two or three times a week. This can be accomplished by putting the iguana's cage outdoors or on a sunny window ledge. Be sure that you provide a shaded area in the cage.