Green Iguanas Care Sheet

The green iguana is the number one reptile pet that ends up abandoned at humane shelters or euthanized each year. They have very special requirements, which can be almost impossible for some people to meet. They are also commonly aggressive and potentially dangerous as adults. They aren’t a pet that the novice reptile owner should keep. If one does decide to take on the task of properly keeping one of these large lizards, reading and research is in order. The number one thing that could keep more iguanas happy and healthy is a little education.

To begin, the green iguana (iguana iguana) is native ranging from Mexico down through Central America and into South America. The areas in which they are found range from arid dry climate areas to wet rainforests lush with plant life. They range from the cool Atlantic coastline to the warm airs of the Pacific. Therefore the green iguana can tolerate much in the way of environmental conditions. In the wild they have been recorded as living up to 10 to even 15 years in age. The oldest iguana documented in captivity was 29 years old. This means that when one decides to purchase one of these pets they should be ready for a long-term commitment.

“Young iguanas are very green and blend in well with their habitat--the leafy dim lower levels of the rain forest canopy. Their tail is striped to help them disappear while lying still on a branch; their spots and stripes of body color also help them blend in. Older iguanas live higher up in the canopy where it is lighter and somewhat drier. In captivity, young iguanas require a more humid environment; keep them at 70-80%, a level that is usually significantly higher than ambient room humidity (Kaplan, 2002).” There are several ways in which to do this. A large water source should be available for the juvenile iguana to submerge itself in. There should also be several mistings through out the day to keep the air nice and humid. A humidifier can be purchased relatively cheap at any department store and can be placed next to the enclosure (if it is screened in). A hygrometer should be purchased so that you can monitor the exact levels of humidity that your young iguana is getting. As they get older the humidity level can be decreased but should be maintained in a relative humidity level of about 70 %.

Heating is another element in which care has to be taken with the green iguana. Ambient temperatures in the enclosure should range from 75º to 88º F. There should be at least one basking area that ranges from 88º to 95º to allow for thermoregulation. If an iguana is not allowed to reach these high temperatures they will not be able to digest their food. If the temperatures are too low not only is digestion an issue but also many health problems will arise.

Also, you’ll want to make sure that the temperature does not exceed 95º F. Like with being too cold, being too hot is also detrimental to an iguana’s health. Iguanas that become too hot will not necessarily move out of the basking area. The reason why is unknown but care should be taken that they are not exposed to such extreme temperatures; hyperthermia is just as lethal as hypothermia. At night, a specifically designed nocturnal heat emitter can be used to keep the temperatures up. Also a heat pad under the tank works fine as well. Nighttime temperatures should not drop below 70º for an adult iguana or 73º for a neonate or juvenile iguana.

Lighting is another area that is essential in keeping an iguana happy and healthy. Green iguanas need ultra violet radiation in order to metabolize their food. Purchasing a full spectrum UVB bulb from any local pet store can provide this type of lighting. UVB triggers a chemical reaction in the skin that ultimately results in the body's formation of vitamin D3. Without sufficient D3, iguanas cannot metabolize enough calcium to keep their cells functioning and bones strong. To be effective, UVB-producing fluorescent lights must be no farther than 18 inches from the iguana; no more than 10 inches away is better. The amount of UVB disperses very rapidly over distance, so any farther away than this and your iguana will not get enough UVB. This is why tall cages with relatively little width are inappropriate. If at all possible have full spectrum lighting available through out the enclosure, not just along the top. Remember that UVB does not diffuse through glass so there should be screen between the bulb and the iguana not glass!

Iguanas, like all other terrestrial vertebrates, operate on a daily cycle that includes a distinct dark period (night, also called scotophase) and light period (day, also called photo phase). The two daily periods are generally referred to as "photoperiod". In the tropics, the day light period is equal in length to the night dark period, both being 12 hours long. The farther north or south you get from the equator, seasonal changes: the days becoming shorter and nights longer in winter, with the opposite happening during the summer. Since our iguanas are tropical lizards, their daily photoperiod should be on a 12:12 photophase: scotophase cycle. Why should you be concerned about the number of hours of dark and light your iguana is exposed to? Because if we do them wrong, the iguana's stress levels, immune and endocrine function, digestion, growth and development, breeding season behavior, and more will be adversely affected (Kaplan).

In the wild green iguanas consume many varieties of plants and are primarily folivores, which means that they consume leafy material almost exclusively. Unfortunately, the types of plants that they eat only grow in Central and South America. Therefore green iguanas should be offered a wide variety of fruits and vegetables in order to ensure that they will receive the proper amounts of nutrients they need to survive. Some common fruits and vegetables that can be used as a staple include acorn squash, alfalfa, butternut squash, prickly pear cactus leaves, collard greens, dandelion greens, endive, mango, papaya, and parsnip just to name a few. Just remember when feeding your green iguana that variety is important to ensure balance in a diet. Green iguanas should never be fed insects. This is a common mistake that many people make. Insects are to high in protein and cause excess strain on the kidneys. Another important aspect with diet is calcium. Calcium cannot be absorbed efficiently unless UVB light is provided and the calcium level should be roughly twice that of the phosphorus level. If this balance is not attained metabolic problems, such as metabolic bone disease, can arise. One aspect of digestion that many are unaware of is the inoculation of important microbes into the intestines of the green iguana. Because green iguanas are hindgut fermentors, like horses, they need a certain amount of bacteria in their intestines to aid in the digestion of food. Many of the food items that they eat are composed of cellulose, which cannot be broken down by normal stomach acids. These bacteria are not present in the green iguana at birth and therefore must be introduced. This is accomplished by a process known as coprophagy. This is where the young iguana ingests fecal matter from an older iguana that has a colony of bacteria proliferating its digestive tract. I know this sounds disgusting, but is very necessary for an iguana’s survival.

If you are still interested in owning a green iguana make sure you do your research. If properly cared for an iguana can be a rewarding reptile to keep. Aggression, nutritional deficiencies, specific temperature requirements, and the fact that these lizards get very large are all aspects that can be potential problems. Make sure that you consult with your veterinarian if you have any concerns regarding your lizards health and well being.