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Warren Woods Veterinary Hospital

Green Iguana: Care and Husbandry

The Green Iguana is a popular reptile pet in the United States and the most common species of pet iguana. The green iguana is found in Central and South America and the Caribbean Islands. They are an arboreal species, which means they spend most of their time in trees and they live in areas of tropical rainforest. Iguanas are diurnal, meaning they are most active during the day. Unlike some other pet reptiles, they are strict herbivores. They can grow to lengths of four to six feet and with proper care can live up to fifteen years. Iguana colors range from bright green to dull grayish-green to provide camouflage in their natural environment. They have rough skin, pointed spines along their backs, long tails, and long claws for climbing and grasping. They have excellent vision and a highly-developed sense of hearing and smell. Their long tail is used to help maintain balance and also as a defense mechanism; a strike from an iguana’s tail can be very painful. They are good swimmers and can run quickly across the ground if alarmed. Males are usually larger in size and have a dewlap, which is a flap of skin under the chin. This dewlap is used to intimidate predators or to impress females. Males also have much larger and more visible femoral pores, which are located along the inner thigh.

Iguanas make good pets if provided with proper care and socialization. It is essential to continue to handle and socialize an iguana to reinforce the bond with the owner. As iguanas mature they may become very aggressive and should not be allowed unsupervised around children or other animals. It is important to consider this before choosing an iguana as a pet.

Since green iguanas are arboreal they require a tall enclosure with a number of branches and vines for climbing. The height and length of the enclosure should be at least three times the length and height of the iguana. Iguana enclosures may need to be custom built, as most commercially available reptile tanks are not large enough for an adult. The perfect green iguana enclosure would be a full room set up with proper lighting and climate. If a room is not available, the largest enclosure possible should be provided. A young iguana can be kept in an aquarium no smaller than 55 gallons. The initial investment in obtaining an iguana may be affordable but the cost of proper care, feeding, and habitat can become expensive as the animal grows.

Acceptable substrate for the bottom of your enclosure can include paper towels, newspaper, butcher paper, terrarium liners, rabbit alfalfa food pellets or recycled paper products. Calcium sand is not a good choice because it can be ingested which may cause intestinal impaction. Wood shavings, walnut shells and sand are all inappropriate choices as these can be harmful if ingested, can carry parasites and irritating dusts and oils.

Iguanas require a variety of vines and branches in their enclosure so they can spend the majority of their time off of the ground. Imitation plants will last longer than live plants because they won’t get damaged by the iguana walking and climbing on them. Branches just slightly larger in diameter than the animal's girth are needed for climbing and should be strong enough to support their weight. The iguana will also need a sheltered area in which it can hide or sleep. The reptile should be monitored to prevent it from attempting to ingest the leaves on the branches and vines as this may cause intestinal impaction.

Iguanas can be very territorial and should be housed alone regardless of their gender. Iguanas housed together will fight which may result in severe injury or death. Iguanas should not be housed with different species of reptiles due to the risk of fighting and the possibility of disease transmission. If the iguana is allowed out of the cage it should be closely monitored. Iguana proof the area by removing clothing, shoes, toys, paper items, loose change, or any other items that the reptile may pick up and chew or ingest. Iguanas may chew on electrical cords or strings so these items should be removed as well.

An iguana’s natural habitat is tropical so the humidity level should remain at 80% and be monitored by a hygrometer. Humidity can be maintained with the aid of an automatic mister, fogging system, waterfall or frequent hand-misting of the enclosure. The habitat should also contain a clean water source large enough for the iguana sit in and soak. The water dish will also aid in keeping the humidity in the enclosure at the proper level. Iguanas might not recognize this as a water source so it is important to mist them lightly every day to keep them hydrated. A warm water soak once weekly is recommended to help keep them hydrated and to help them defecate.

The enclosure should be cleaned with mild soap and warm water as needed. Thorough cleaning can usually be done once monthly with spot cleaning done during the week. It is also important to thoroughly wash your hands after handling.

A heat lamp, ceramic heat emitter is important to maintain the appropriate temperature. The ideal temperature for an iguana is 80-95 degrees Fahrenheit with one side being slightly cooler (about 5 degrees) than the other. This difference in temperature allows your iguana to cool off and avoid overheating. These temperatures are monitored with two thermometers, one on each side of the cage. Your iguana should have 12 hours of daylight (white light) and 12 hours of darkness for its natural biorhythms. A timer purchased from a pet supply store or hardware store can be utilized to maintain this twelve hour light cycle. At night, the temperature in the enclosure should drop slightly, about 10 degrees, as it would in their natural habitat. Night temperatures should also be closely monitored and ceramic heat emitters, red, blue or purple reptile night bulbs can aid in increasing night temperatures if needed. Always use reptile specific heat bulbs which have modifications that benefit the reptile and helps stimulates eating.

An ultraviolet light is essential for the health of iguanas. This reptile specific bulb produces UVA and UVB rays and is purchased from your local pet supply store. The UVB rays are important for the natural production of vitamin D which helps the iguana absorb calcium from its diet. Without the UV bulb your iguana cannot properly absorb calcium which leads to metabolic bone disease. UV bulbs for reptiles come in two different forms the compact (coil) bulb and the linear florescent tube. While there are many companies that produce UV bulbs, Zoo Med and Zilla are recommended. Follow manufacturer recommendations to determine the type of UV bulb you purchase, and the distance to place the bulb from your iguana. All UV bulbs need to be changed every 6-12 months based on manufacturer’s recommendations. After that time, even if the bulb still turns on it is not producing the vital rays your iguana needs for calcium metabolism. Plastic and glass windows are designed to block UVB rays so keeping the tank by a window will not provide essential UVB rays. It is ideal to provide monitored time outside on a warm day in an escape proof enclosure with access to shelter. Natural sunlight is the best source of essential UV rays.

Heat rocks should not be used as they can cause burns since reptiles do not sense a “localized” temperature. Heating pads under the tank may be used with supervision. Place your hand on the area of the tank with the heating pad; if it is too hot for your hand to rest on for long periods of time then it is too hot for your iguana.

Green iguanas are herbivores and eat vegetation in their natural habitat. It is important to provide a variety of foods so the iguana has proper nutrition. Safe foods to feed include dandelion greens, collard greens, chicory greens, escarole, endive, romaine, mustard and turnip greens. Iceberg lettuce has no nutritional value and should not be fed. Other vegetables that are safe to feed include green beans, peas, cucumber, zucchini, and bell peppers. Orange vegetables such as carrot, squash, and sweet potato are very good sources of vitamin A. The iguana may also be fed fruits such as strawberries, blueberries, raspberries, apples, grapes, cantaloupe, papaya, mango, and bananas but the bulk of their diet should be vegetables. The best time to feed an iguana is in the morning after they have had a few hours to warm up.

Spinach, broccoli, cabbage, cauliflower, and other cruciferous vegetables cannot be fed as they contain oxalates that bind calcium intake. Insects, meat products or cat/dog food should not be feed to iguanas. The protein in those foods is too high and can cause health issues including poor bone formation, bladder stones and liver problems.

Iguanas do not produce enough calcium themselves and therefore it must be supplemented in their food. This can be done by purchasing a calcium D3 powder from your local area pet store. This powder is sprinkled on food 3-4 times a week for juvenile iguanas (under one year old) or breeding females and 2-3 times a week for adult iguanas.

Hibernation is an instinctual act, usually during the cooler months, during which your iguana’s appetite and activity will drastically decrease. It is not necessary for a pet iguana to hibernate and it may be dangerous if not done properly. Hibernation should only be attempted by an experienced keeper with the aid of a reptile veterinarian. This act is stimulated by your iguana’s natural instincts along with differences in the temperature of the environment and the shortening of days. Maintaining the same temperature and light cycle in your enclosure during the winter months will help prevent hibernation.

An annual examination by a reptile veterinarian is very important to ensure the health of a pet iguana. Reptiles are very good at hiding illness; this is an instinctive behavior to protect them in the wild. It is important to see a reptile veterinarian as soon as any sign of illness is noticed. Common diseases that affect iguanas include metabolic bone disease, abrasions, bacterial infections, mouth rot and rear leg paralysis. A pet iguana should be neutered (spay or castration) to aid in the prevention of diseases of the reproduction system and to prevent egg laying in females. It can also decrease aggression, especially in males.