Green Iguana (Iguana iguana)

Green iguanas are found throughout tropical and subtropical North and South America. Green iguanas are common in Mexico and south throughout Central America and down through South America to Paraguay and Argentina. Green iguanas also occur throughout the Lesser Antilles and, in the past 20 years or so, the Greater Antilles and Southern Florida. In the Greater Antilles and southern Florida, green iguanas are an introduced species.

There is a definitive difference in the physical appearance of green iguanas depending on their locale. First, the South American green iguana population used to have the taxonomic name of Iguana iguana iguana. South American green iguanas are much less cold tolerant than the Central American green iguanas once referred to as Iguana iguana rhinolopha. All these subspecies are now synonymous, and there is only one recognized species: Iguana iguana. Green iguanas from some parts of Central America have horns on their noses ranging in size from small bumps to quite large flexible horns over a ½ inch long.

Green Iguana Availability

The green iguana is arguably the most common reptile in the pet trade today. Green iguanas are readily available and almost one million are imported into the United States annually as babies. It is true that these wonderful lizards make personable pets, but very few people who purchase them can meet the requirements of an adult green iguana.

If you are considering keeping a pet green iguana, I urge you to consider adopting one from a reptile rescue. Unless you can provide adequate facilities for an adult green iguana, you should not consider purchasing a green iguana as a pet.

Currently, there are several beautiful designer morph green iguanas available on the market. The hobbyist may now purchase erythrystic iguanas, blue iguanas (axanthic) and albino iguanas. Contrary to popular belief, albino green iguanas do well in full sun and with inside ultraviolet light. The sun has no adverse effect whatsoever on the albino iguanas. Many of these morphs, such as the albinos, are still quite expensive, but over time they will likely become more affordable.

Green Iguana Size

Green iguanas may reach lengths of 6 to 7 feet and weigh around 20 pounds. Male green iguanas reach a greater length than female green iguanas, which rarely exceed 5 feet in length. Additionally, mature male green iguanas have larger spikes going down their back and large femoral pores on the underside of their back legs.

Albino iguana

PHOTO CREDIT: TOM CRUTCHFIELD

Albino iguana.

Green Iguana Life Span

If kept properly, green iguanas live to be 15 to 20 years old.

Green Iguana Caging

A 20-gallon-long aquarium will suffice as caging for baby and young green iguanas up to about 18 inches long. We acclimate our baby albino green iguanas in this kind of enclosure. If you put a newly acquired small lizard in a HUGE enclosure, they sometimes have difficulty finding their food and water. Additionally, these smaller tanks allow green iguanas to understand that you are not a predator that intends to eat them. All in all, a small tank is much better than a large cage for a baby green iguana.

An adult green iguana needs LOTS of space. That cute little baby green iguana will grow at a very rapid rate to a 6-foot-long dinosaur with special needs that the average owner cannot provide.

An adult green iguana requires an enclosure at least 12 feet long by 6 feet wide by 6 feet high. The height of 6 feet is very important as, these lizards are primarily arboreal in nature. A good rule of thumb is to provide a cage that is at least twice as long as the iguana, with a width at least the same length as the lizard. You cannot house adult males in the same cage, or they will fight.

The cage parameters and temperature gradients are easier met for adult iguanas in some type of wire enclosure. How you construct or purchase the enclosure is not as important as providing the proper size and temperatures needed to house an adult iguana.

iguana enclosure

PHOTO CREDIT: TOM CRUTCHFIELD

Adult green iguanas in a 15 by 18 by 6 foot breeding cage.

Green Iguana Substrate

The substrates we use for our green iguanas are plain rabbit pellets or alfalfa pellets. This is done because substrate is often eaten by neonate green iguanas by accident, and eating these pellets will not cause as much harm as other substrates. However, if I ever saw baby green iguanas eating the rabbit pellets or alfalfa pellets deliberately I would remove them. If I were keeping larger green iguanas inside I would use cypress mulch.

Green Iguana Lighting and Temperature

Green iguanas need lots of heat. With a baby green iguana, one heat bulb is sufficient, but with an adult green iguana, you need a bank of at least six lights in order for the green iguana to adequately heat up its entire body.

I suggest using incandescent heat bulbs and a double row of fluorescent UV bulbs so that vitamin D synthesis is possible. UVA and UVB should both be provided for optimum results. Strong UV fluorescent lights are needed to prevent metabolic bone disease.

A hotspot of at least 120 degrees Fahrenheit should be provided. Additionally, the heat should come from above the green iguana, so the parietal eye is engaged, thus enabling the green iguana to thermoregulate as required. Located directly on top of the head of green iguanas, behind their eyes, is an unusual scalelike organ called a parietal eye or pineal body. This scalelike sensory organ can detect light, dark and movement. The parietal eye is extremely important for thermoregulation purposes and to warn green iguanas of predators approaching from above, such as birds of prey.

Of course, parts of the cage should be cooler, so the green iguana is able to choose the temperature it likes by thermoregulating between hotter and cooler temperatures. A high end of 120 degrees and a cooler end in the low to mid 80s works well with green iguanas. The real key is allowing the green iguana to choose its own body temperature, and all the keeper has to do is provide the means for it to do so.

DO NOT USE HOT ROCKS, HEAT PADS OR ANY OTHER HEAT SOURCE COMING FROM THE FLOOR. Captive green iguanas often burn themselves when substrate heaters such as "hot rocks" are used as a heat source. The reason for this is that the parietal eye is not engaged, and green iguanas do not recognize these as heat and attempt to bask. The iguanas’ legs and stomach are usually burned because they do not realize how hot they are getting. I have seen second- and third-degree burns serious enough to cause death from using a hot rock as a heat source. Remember these two things very well: provide the adequate size and the adequate temperature.

Green Iguana Water

Water should always be made available. Remember that smaller green iguanas, especially babies, may not be able to locate their water bowl. Because of this, it is vital that you mist them daily and soak them at least twice weekly in order to ensure that they are well hydrated.

If you start with a juvenile green iguana, it is beneficial to mist them as well as to occasionally put them in their water dish. If possible, it is best to provide a water container large enough for the lizard to get into and soak. In the wild, green iguanas always live near water and are excellent swimmers.

Green Iguana Food

Green iguana dietary needs are easily met both with raw natural foods that can be purchased in a supermarket and commercially prepared "Iguana Food." Vegetables such as collard greens, turnip greens, dandelions, yellow squash, whole green beans, etc., are excellent food for your green iguana. We also provide fruit about once a week. A green iguana diet that is high in fruit can cause diarrhea.

Food preparation for small green iguanas is slightly different than for adult green iguanas. When cutting up raw vegetables, it is wise to cut each piece to the proper size for the green iguana to pick up and easily swallow whole. Remember that green iguanas cannot chew their food and have to swallow it in one piece.

Additionally, there are great commercial foods made by Zoo Med, Mazuri, Rep-Cal and others that are nutritionally sound and that green iguanas like to eat. If you are using a commercial food source such as Mazuri Tortoise Chow, which we rely heavily on, you must moisten it as needed so the juvenile green iguanas are able to eat it. My large green iguanas will simply pick up the dry pieces and swallow them.

You should add a calcium supplement, such as Osteoform, to the green iguana food about once a week. Under NO circumstances should you give green iguanas a diet that is high in protein. If you do, over time this will lead to renal failure and the death of the iguana.

We also provide live hibiscus plants of the proper size to fit into the cage as not only a food supplement but also for the juvenile green iguanas to climb on. Hibiscus plants can be purchased at most garden centers, but remember that these may have been sprayed with an insecticide. We always spray any new plant with water thoroughly and sit it outside for a minimum of 14 days before placing it into an enclosure as a food source and shelter.

Green Iguana Handling and Temperament

Baby green iguanas generally do not bite, but excessive handling should be avoided until the iguana gets used to its new home. Green iguanas make intelligent, friendly pets. Unlike snakes and many other herps, iguanas have the capability of identifying their caretakers, and some have remarkable personalities. Over time they may become quite affectionate and are among the most rewarding of all reptiles to keep.

I implore you to NOT purchase a green iguana on impulse just because they are cute. Unfortunately, baby green iguanas are now so inexpensive that they have become what I call "a disposable pet." Many of the green iguanas that are purchased perish because of the lack of knowledge and ability of the keeper. Please think before you buy a green iguana and remember that as with all animals, they are living things. If you have read this article and still want an iguana as a pet, you will not be disappointed, as green iguanas are one of the finest reptiles available today.