The Green Iguana (Iguana iguana) is a diurnal, arboreal, tropical lizard of Central and South America. They have also been introduced into south Florida. They are only rarely bred in captivity. In the wild, iguanas are virtually herbivorous, eating fibrous jungle leaves, flowers, and fruits. They rely on fermentation of complex carbohydrates in the colon to produce 30-40% of the energy available for their diet. The required bacteria are acquired in hatchlings by eating feces of the adult iguanas. Iguanas facilitate the fermentation process and regulate their body temperature by basking in the sun, seeking temperatures above 85 F (30 C). Their social rank is reflected in the prominence of their basking sites. Adult animals may reach a length of six feet and may weigh as much as 15 pounds. Large specimens should be handled with caution.

Care in Captivity: Temperature, humidity, and light requirements for an iguana are critical if the animal is to survive in captivity. Housing can be large glass, plexiglass, or wood cages. A 20 gallon or larger aquarium is a good starting size, as these reptiles grow at a rapid rate in the first few months of life. The cage should be lined with newspaper, artificial grass, or indoor-outdoor carpet, ease of cleaning being the most important consideration. Gravel, sand, and soil should be sugges ted.avoided as it is commonly ingested leading to impaction and may contribute to dermatitis if not cleaned regularly. A variety of broad limbs, rocks, or pieces of bark should be provided as basking sites.

Temperature: Heat should be provided by a radiant source; a 60 to 100 watt incandescent bulb is usually adequate, as, being a basking animal, the iguana does better with a source of radiant heat. Hot-pads, hot-rocks, and heating tape are common causes of burns and typically do not provide the heat necessary for the animal to obtain its preferred body temperature. Daytime temperatures of 85 to 95 F and a 95-100 F "basking spot" are optimum. Night time temperatures should not drop below 70-75 F. A colored bulb can be used if needed.

Diet: Captive young iguanas do poorly eating a diet of grocery store vegetables. Perhaps because of their rapid rate of growth, it is essential that they be supplement with protein and a balanced source of calcium. Strangely, however, if adult iguanas are fed in a similar fashion, a variety of ailments related to over supplementation arise. The following feeding regimens are suggested.

Medium or adolescent iguanas: (one to one and one-half foot, nose to vent) are fed 25% bird pellets* and 75% plant material.

Large or adult iguanas: (larger than one and one half feet, or any size once growth has ceased) are fed only 10 to 15% bird pellets* and 85-90% plant material.

Light: Iguanas have a primitive endocrine system regulated by a photosensitive pineal gland located under a transparent scale at the crown of their head. We recommend a consistent photoperiod of 14 hours of light and 10 hours of dark until the time that the iguana stops growing. An ultraviolet light source (Vita-Lite, Duro-Test) should be available within two feet of the lizard to aid in the conversion of vitamin D and, perhaps, other physiological functions. Remember the UV light will not go through glass or plexiglass.

Diseases: There are numerous disease processes that affect iguanas; most are related to inadequate/incorrect nutrition or husbandry. Some of the most common are metabolic Bone Disease (too little vitamin D, calcium, or ultra-violet light), metastatic mineralization of soft tissues (too much protein, calcium, or vitamin D), necrotic dermatitis (Blister disease), burns (from heating pads or hot rocks), mouth rot, and egg retention. All of these are treatable and early diagnosis is essential. Your veterinarian should be consulted at the first symptoms or unusual appearance of the iguana.

Brainerd Hills Veterinary Hospital

Journal of Small Exotic Animal Medicine Vol.I No. 3, 1992

* Iguana diet recommendations were revised from Dr. Jenkins by Dr. Barbara K. Newton on 10/25/97 Revised 10/25/1997 Corel WP