Introduction:

The green iguana is a lizard native to Central and South America. They are daylight active (diurnal) and dwell in trees (arboreal). Their day is spent foraging for food and basking in trees. With appropriate care most iguanas can live 10 - 15 + years and reach 6 feet or more in length.

Environment:

Housing is one of the first considerations in keeping your iguana happy. It is best to start with a high 20 or a 29 gallon tank, but expect to purchase or build a larger cage in the future. Iguanas grow fairly quickly and under the right conditions, can grow to be 2 feet at 1 year of age. At 6 feet, they will require a sizable enclosure.

Newspaper is an ideal cage liner since it is inexpensive and easy to clean. Astroturf (indoor/outdoor carpeting) also works well, but at least two pieces are needed to allow for cleaning and drying of one piece while the other is in the cage. Alfalfa pellets (rabbit chow) can also be used in the bottom of the cage and can be eaten. Bark, corncob, and cat litter should not be used as it will cause intestinal blockage if ingested.

The cage should be cleaned as needed, which is usually on a daily basis, and disinfected weekly. Bleach diluted with water is appropriate. Rinse thoroughly with water and let dry after disinfecting. Do not use Lysol as it is toxic to reptiles.

Visual security is desirable and can be accomplished using plastic plants, clay pots, cork bark, and other items that won't be eaten. Rocks work well because they act as an abrasive surface to aid in shedding skin. The iguana sheds its skin in patches. The frequency determines its growth rate.

Water is also an important aid in allowing the skin to shed. A shallow dish of water, or soak pit, is a necessity for smaller iguanas. The bathtub is a good alternative to a soak pit for larger animals. Misting with a spray bottle 3 - 4 times weekly can also help keep an iguana's skin hydrated. Many times the soak pit is used as a toliet and must be kept clean. Clean drinking water must always be available. Many iguanas will lap water droplets from plastic plants or other items in the cage when misted. This can also help keep the humidity in the desired 50 - 75 percent range.

Climbing material is usually well liked. Branches that reach up to the heat source is the preferred way to allow for basking. Make certain the lizard can't get too close to the heat in order to avoid burns. Do not allow your lizard to roam your house. You may not be able to find him again.

Temperature:

Correct temperature is required for normal activity and physiologic functions such as food digestion and immunity. A temperature gradient from one end of the cage to the other is mandatory. This way the lizard can choose the temperature it wants by moving about in the cage. The temperature should range from near 100 degrees at a basking site to about 75 degrees at the opposite end of the enclosure. For mature iguanas the nighttime temperature can dip to 60 - 75 degrees.

The basking site is best provided by the use of a heat lamp. This can be an incandescent bulb; however, these cannot be left on 24 hours a day due to the white light that is emitted. This would mimic 24 hours of daylight and be stressful to the animal. Better alternatives are red heat lamps, black heat lamps for use at night, or ceramic heat bulbs that do not emit white light. All can be kept on for 24 hours to ensure the temperature doesn't drop too low at night. To allow some cooling at night, the lamp can be moved farther from the cage.

The background temperature of the enclosure should be about 75 degrees F. If the heat lamp doesn't allow for this then a second heat source is required. Under the tank heat is the preferred method utilizing an appropriate reptile heat tape or heating pad. Thermometers are a must for monitoring the temperature both at the basking site (95 - 100 degrees) and the background temperature away from the basking site (75 degrees). It is also critical to prevent the lizard from getting so close to the heat source as it will be burned.

Lighting:

To help prevent bone disease and to give your iguana a day/night cycle, it is important to supply it with full spectrum lighting. Iguanas require a day/night cycle of about 14 hours daylight and 10 hours of darkness. This ratio can be reversed during the winter to provide 10 hours of daylight. Full spectrum bulbs are made especially for this purpose. Vita Lite and Zoo Med are two popular brands. These lights can not be covered by glass or Plexiglas as this filters out the important ultraviolet rays. Screen is suitable to place between the light source and the lizard.

The other important function of lighting is for the syntheses of vitamin D within the skin. Vitamin D is important in causing calcium to be absorbed from intestines. Calcium deficiency is one of the most common diseases of iguanas. A lack of ultraviolet light rays are felt to be a contributing factor in the development of calcium deficiency and its resultant bone disease. Although there are a number of commercial full spectrum bulbs available, there is no substitute for natural sunlight, again, unobstructed by glass. Even brief periods of time outside with exposure to natural sunlight can be equivalent to hours of basking under artificial lights. Therefore, during periods of warm weather it is strongly suggested that you take your iguana outside for a nice bask in some real sunshine. Beware: it takes only a few minutes for the enclosure to become an oven which will lead to hyperthermia (sudden death). Only allow access to sunshine under direct supervision.

Nutrition:

The exact dietary requirements for iguanas is unknown, however, by following some basic guidelines we can provide adequate nutrition. Iguanas are herbivores (plant eaters) for their entire lives, although some will readily eat crickets and other insects as well as small rodents. Feeding crickets and other insects is not necessarily recommended. However, if fed, they should only be in limited amounts (up to 5% of the diet). It is generally accepted that the feeding of high protein items such as dog food, monkey biscuits, trout chow, cooked meats, and eggs is wrong and inappropriate. These items are not recommended, although, an occasional treat of one of them is probably not detrimental and may be enjoyed. Avoid cat food due to its excessive protein content.

The diet of young iguanas should vary somewhat from that of mature animals. This is a result of their rapid growth rate and the need for increased calcium in the juvenile iguana's diet. Around 2 years of age they mature and are susceptible to diseases caused by an excess of calcium. This leads to the importance of slight dietary modifications at that time by reducing the amount of calcium supplementation. For juveniles, a powdered calcium -only supplement should be added in small amounts 3 - 4 times weekly and a multi-vitamin/mineral supplement should be sprinkled on the diet 2 - 3 days per week. To reiterate, this involves purchasing two supplements: one multi-vitamin/mineral and one calcium -only supplement (e.g. Repcal) to be used on alternate days. Approaching maturity, around 2 years of age, gradually reduce supplements to the point that calcium is added once weekly and the multi-vitamin/mineral is added once or twice weekly.

Juveniles should be fed once or twice daily and adults can be fed daily (preferred) or every other day. Food items should be finely chopped and mixed thoroughly to promote ingestion of a variety of foodstuffs. Since iguanas are herbivores, appropriate dietary items include, but are not limited to a combination of romaine and leaf lettuce (avoid head lettuce such as iceberg), spinach, broccoli, green beans, peas, alfalfa, parsley, lima beans, yams, rabbit pellets, corn, carrots, beet greens, alfalfa sprouts, kale, collards, mustard greens, escarole, zucchini, yellow squash, bok choy, brussel sprouts, cabbage, and cauliflower. Fruits and berries can make up about 10% of the diet. These items include grapes, raspberries, melons, strawberries, peaches, banana, mango, kiwi, apple, blueberries, and cherries. Natural plants from your home or yard, such as nasturtium flowers, hibiscus flowers and dandelion greens, can also be fed as long as they have not been treated with any pesticides.

Commercial diets are also available and can be fed successfully. It is typically recommended to feed additional items from the above list for variety and completeness. Vitamin and mineral supplements should also be minimized when feeding commercial diets that are supposedly complete and balanced. Current quality iguana diets are produced by Ziegler Brothers, Nutriguana, Reed's, and Zoo Med.