Green Iguana
The green iguana (Iguana iguana) is one of the most frequently purchased reptiles, but is unfortunately also the most frequently seen reptile in the veterinary office due to disease caused by inadequate diet and husbandry. Often you, the owner, is not given proper information as to the needs of the iguana at the time the pet is acquired and it may be weeks to months before the devastating effects of improper diet, internal parasites or incorrect housing conditions take their toil and the pet becomes ill.
This is a very brief overview of iguanas and their needs, but we highly recommend that you purchase a copy of The General Care and Maintenance of the Green Iguana by Philippe de Vosjoli (available at our clinic), which is an invaluable source of detailed information.

Iguanas are diurnal, arboreal, tropical lizards of Central and South America. They have been introduced into south Florida and are bred in captivity with increasing frequency (although primarily in Central America). In the wild, iguanas are virtually herbivorous, eating fibrous jungle leaves, flowers and fruits. They rely on fermentation of complex carbohydrates in their colon to produce 30 to 40% of the energy available from their diet. The required bacteria are acquired in hatchlings by eating the feces of adult iguanas. Iguanas facilitate this fermentation process and regulate their body temperature by basking in the sun, seeking temperatures above 85F (30C). Their social rank is reflected in the prominence of their basking sites. Adult animals may reach a length of 6 feet and weigh as much as 15 pounds, a fact that should be considered when purchasing that cute little green lizard in the pet store! Adult animals require a large amount of cage space and may be quite dangerous to handle. Their razor sharp teeth can inflict serious injuries, and the tail, when lashed, can also cause skin lacerations or eye injuries (not to mention their sharp claws)!

Housing
Providing the proper temperature, humidity and light requirements for an iguana is critical if the animal is to survive in captivity. Iguanas should be housed in large glass, plexiglass or wooden cages. A 20 gallon, or larger, aquarium is a good size to start with as these reptiles grow at a very rapid rate in the first several months of life. The cage should be lined with newspaper, artificial grass (astro-turf) or indoor-outdoor carpet, with ease of cleaning being the most important consideration. Do not use gravel, sand, soil or kitty litter because the iguana may eat pieces of these materials and then develop a potentially fatal intestinal impaction. These materials are also difficult on the animal’s skin and can lead to skin disease if they become dirty or are continually damp.

A water bowl should be provided with fresh water changed daily for the animal to drink out of and soak in. The bathtub or sink is also a good place for a daily swim for your pet. Many pets will defecate only in the water, which can make it easier for cleanup.

Humidity in the tank can be provided by lightly misting the area once daily or with the use of a humidity box. (See attached sheet on construction of the humidity box.)

A hiding area is critical for the animal’s mental wellbeing. The humidity box may be used for this, or any cupboard, wood or plastic container that is of sufficient size for the pet to enter and turn around in will suffice.

Temperature and Lighting
Iguanas are tropical lizards and should have supplemental heat added to their environment. We do not approve of “hot rocks” being used for this purpose. We frequently see serious thermal burns on the underside of baby iguanas caused by the uneven heating of the hot rock that, in some instances, have lead to death. There should be a temperature gradient in the cage, meaning one should not attempt to make the whole environment the same temperature. Under cage heating can be provided by a heating pad left on 24 hours a day and put UNDER the tank so the animal does not have direct contact with it. There are several types of specifically made reptile heaters of varying sizes available, some with thermostatic controls. In addition, the pet needs a “hot basking spot” provided in the cage by an overhead heat and light source. The temperature in this area needs to reach 90F to 100F. This light should be left on only 10-14 hours per day and should be turned off at night. Putting the light on a timer is helpful. Nighttime temperatures may drop to 70F to 75F. Allowing your pet to live at “room temperature” all the time with no chance for thermoregulation will lead to serious health problems over time (it may take several years).

There is ongoing controversy about the usefulness of UV light in the captive iguana’s environment. We know that certain types of UV light are important in helping Vitamin D production in the animal’s skin, which in turn is essential in facilitating the absorption of calcium into the body. The question is whether the various light sources that claim to be most like sunlight are really doing the job. The answer is that there is no substitute for natural sunlight, and none of the light bulbs currently on the market can exactly reproduce sunlight. However, since we live in a climate that prevents us from keeping our pets outdoors all year (and UV rays are blocked out by glass windows) we recommend using light bulbs that provide at least some source of UV rays. Vitalite and Chromalux bulbs are two that we recommend currently and should be placed so that the pet is no more than 2 feet away from the light source. The advantage of Chromalux is that it is also a heat-producing bulb.

We highly recommend, during the warm summer months when the temperature is 80F or higher, that you expose your pet to natural sunlight. We recommend building an outdoor playpen with a shaded area where your pet can spend some time on nice days. Even if you put them on a harness and leash and “sunbathe” together with your pet when you can, the benefit can be tremendous.

Cage mates are NOT recommended. Iguanas are not social animals and the presence of a cage mate may result in serious injury or death. Another phenomenon that has been seen is the less dominant of the two iguanas will not grow properly and will be more sickly than the dominant animal, even in the presence of abundant food and a good environment.
© 2004 Midwest Bird and Exotic Animal Hospital