While there used to be two subspecies of Green Iguana—the Iguana iguana and the Iguana rhinolopha—the only currently recognized species of Green Iguana is the Iguana iguana. This is because there exists too much variety in the differentiating characteristics an iguana shows depending on the geographic location where it lives. There are other species of iguana that are not in the pet trade, such as the marine, rhino, and rock iguanas.
Green Iguana Size
There is a great amount of variation in the potential adult size of green iguanas, depending on the country they came from and the conditions in which they were kept. Generally, adult iguanas will achieve a length between 4 and 5 feet, sometimes reaching up to 6 feet in length.
Some South American male iguanas have reached a length of nearly 7 feet and can weigh up to 18 pounds. Green iguanas that are 6-feet in length or larger are rarely found in captivity.
Green Iguana Lifespan
Green iguanas are relatively long-lived specimens, with the average green iguana living for ten to fifteen years. Some male green iguanas can live in excess of twenty years, with the record held by a male iguana that lived to be between twenty-two and twenty-five.
Green Iguana Appearance
Green iguanas can vary greatly in their appearance and markings, their country of origin and the environment in which they were raised determines much of how they look. Generally speaking though, green iguanas have very long tails, up to three times their body length. Green iguanas also have permanent dewlaps; the turkey-like crest that hangs from their throat. Males always have larger dewlaps than female specimens.
Green iguanas also have one or more enlarged scales right beneath their eardrums, and enlarged neck and back crests. Iguanas resemble little dragons, which is probably why they’re one of the most popular lizards to keep as pets.
In addition to the size of their crests fluctuating, green iguanas can take on a spectrum of colors, from dark greens and browns to lighter blues, turquoises, and reds. They can also have a banded appearance, or odd patterning, however these green iguana varieties are quite rare.
Green Iguana Care Level
There are a few factors that limit the pet potential of green iguanas, landing them in the recommended intermediate-to-advanced care level. Once they are sexually mature, green iguanas, males in particular, can become quite aggressive. Additionally, green iguanas can harbor Salmonella, which presents health risks to the animal’s owners and family members if proper hygiene is not followed. More important, they have high care requirements and can be difficult to handle due to their size and weapons-nails, tail, and mouth.
Green Iguana Diet
Don’t be fooled by its fierce look, the green iguana doesn’t eat meat. Its favorite foods are of the leafier variety. The bulk of your pet green iguana’s diet should comprise of leafy greens, vegetables and fruits.
In addition to fresh salad greens and veggies from the supermarket, you can supplement your green iguana’s diet with leaves and blossoms you find in the wild, commercial iguana food, and dietary supplements and vitamins. Iguanas are active during the daytime; feed them the bulk of their food in the morning. And always provide your iguana with plenty of clean, fresh water to drink.
When feeding your iguana, you can feed it as much nutritionally balanced salad as it can eat during daylight hours. Iguanas won’t become obese when fed high-fiber diets. However, you shouldn’t feed a young and growing iguana treats. This can stunt the animal’s growth and prevent it from reaching it’s full genetic potential.
Never feed your iguana high-fat foods or non-iguana foods like potato chips, dessert, tea, chocolate, alcohol, certain candies, caffeine, etc.
Green Iguana Health
Common Health Issues in Green Iguanas
The green iguana is prone to contracting a variety of diseases and disorders, but the good news is that due to its huge popularity, veterinarians have a pretty uniform standard of care. The following is a list and short summary of green iguana diseases and disorders, from most common to least common.
If your pet iguana is showing any symptoms described below, we recommend consulting your veterinarian.
Nutritional & Metabolic Disorders
Metabolic Bone Disease (MBD) is the name given to a group of complex bone conditions regularly seen in lizards. Usually, MBDs are related to a lack of calcium in the diet or lack of proper ultraviolet lighting. However, MBDs can be caused by kidney disease and parathyroid tumors as well.
Symptoms of MBD in green iguanas includeswollen andpainful limbs; the bones of the jaw taking on a misshapen rubbery appearance, preventing the animal from being able to eat; and an involuntary twitching of the muscles. This muscle twitching is known as “tetany,” and signals that the animal is in critical condition or that seizures may occur soon.
Treatments for MDB include Exposure to UV light to provide Vitamin D, a dietary correction (in early cases only), and hospitalization with appropriate medications.
Visceral gout in green iguanas is a disorder where the iguana is unable to process the protein it ingests, or is fed too much protein to break down properly.
Visceral gout is a common cause of death in older green iguanas that are fed too much meat or canned dog or cat food. Do not feed your iguanas dog or cat food.
Secondary visceral gout occurs when the iguana isn’t given enough water and becomes dehydrated and unable to process even normal levels of protein and uric acid. Symptoms of visceral gout in green iguanas include irritation and inflammation around the affected tissue areas. If you follow proper dietary requirements, your green iguana shouldn’t contract visceral gout. Severely damaged kidneys can result in renal disease and death.
Infectious Diseases and Parasites
There is a litany of infectious diseases that green iguanas can contract, including postorbital abscesses, oral abscesses, gum and respiratory diseases, bacterial skin , and fungal diseases, not to mention tail cysts.
Reptiles have primitive immune systems, so if your iguana is suffering from an infectious disease, do whatever you can to help stimulate the lizard’s immune system, whether that means including more nutrition, proper hydration, or adjusting environmental factors. If you suspect your iguana is sick or infected, always seek veterinary assistance.
Both internal and external parasites pose a problem when it comes to green iguanas. Internal parasites interfere with food processing and the absorption of nutrients, causing discomfort and damaging the gastrointestinal tract. It’s important to have fecal examinations performed on your pet to determine whether or not they’re dealing with an internal parasite, even though you may not see them in the stool.
Internal parasites include nematodes, pinworms, hookworms, cestodes, coccidial agents, and protozoan agents. See your veterinarian for recommended medications and guidance in administering them.
The most common external parasites on green iguanas are ticks and mites. Ticks can be removed by firmly pulling on them until they release, then by treating the bite area with a topical antibiotic like Neosporin. Mites are a bit trickier to take care of because they multiply extremely fast. Heavy mite infestations on green iguanas can look like fuzzy white or dark colored spots that move on the animal’s body. When mites infest an iguana, the lizard will soak in its water bowl for prolonged periods in an attempt to rid itself of the pests. In order to successfully take care of a mite infestation you’ll need to treat your pet as well as thoroughly cleaning its cage and furnishings.
Green Iguana Behavior
Green iguanas undergo different stages throughout their lives that aid in dictating their behavior.
After the iguana is born, it is in the hatchling/juvenile stage and is quite flight prone. This is normal. Captive bred juvenile iguanas won’t show aggression or territoriality, but as they get larger they may tail whip when frightened. The hatchling/juvenile stage is also marked by quick growth.
When the iguana enters sexual maturity its behavior will change again, usually becoming a bit more aggressive, especially during breeding season. This stage lasts until the iguana is about five years old, when it will stop growing and enter into its mature adult stage. By the time your iguana has matured it will start to show less activity, becoming active in brief spurts.
Supplies for the Green Iguana’s Environment
Aquarium Tank or Terrarium Setup
Green iguanas grow at an extremely fast rate during their first years and need a home that will fit their size. A 29 to 30 gallon glass tank is a good starter size, but you’ll need to upgrade to a 55-gallon tank once your iguana reaches 2.5 to 3 feet in length. If your pet grows larger than 4 feet you will need a custom enclosure to comfortably house them.
A good rule of thumb is that your green iguana enclosure should always be at least 1.5 times the length of the animal in width, and 3/4 the length of the animal in height.
As for the substrate of your iguana’s cage, you can go as simple or fancy as you like. Plain newspaper or brown wrapping paper work just as well as fine- to medium-grade orchid barks. Just keep in mind that whatever substrate you choose, you’ll have to clean and replace regularly. The good thing is, iguanas tend to defecate in the same place, which makes spot cleaning and changing simple.
Another substrate option is alfalfa pellets (rabbit pellets). Alfalfa pellets are inexpensive, absorbent, and can be safely ingested.
Branches and Shelters
Green iguanas are arboreal lizards, meaning they like to spend their days lounging in trees and branches. It’s important to provide branches in iguana enclosures as basking and resting sites. Arrange the branches in a way that they run diagonally across the enclosure, allowing enough room between the branches and any spotlights so that the iguana doesn’t burn itself.
When adding a new pet iguana to an already existing household, it’s important to provide a hiding place initially. Allow the new iguana to become more comfortable in its new home before removing the hiding place and forcing interaction.
Heat and Light
Temperature is arguably the most important factor when it comes to successfully rearing and maintaining green iguanas.
As with all other reptiles, maintaining proper body temperatures is essential to the animal’s metabolism. Always make sure you have adequate lighting and heating in your iguana’s habitat.
In order to properly digest their food, green iguanas need to be able to raise their body temperature to 85-90 degrees Fahrenheit. You can achieve the proper temperatures by placing an incandescent spotlight above the screen or outside of the enclosure and pointing it at a basking area. Use multiple thermometers to ensure the temperature of the basking area nearest the bulb does not exceed 100 degrees Fahrenheit.
Hot rocks for heat are not recommended. Green iguanas do not do well with hot rocks; they can get thermal burns from too much exposure. In the wild, green iguanas thermoregulate by pointing themselves towards the sun, not by basking on hot rocks and surfaces.
While many iguana experts have successfully kept animals for ten years or more without the help of UV exposure, new research suggests that exposure to UV-B can help the animal synthesize vitamin D3.
Humidity (Air Moisture)
Green iguanas also enjoy a humidity level between 70 and 80 percent, which you can achieve by providing a big bowl of clean drinking water and occasional misting.
It is a good idea to invest in a hygrometer to ensure the proper humidity level is maintained. When misting, the best way to do so is to lightly mist your iguana a few hours before you turn the lights off for the night.
With proper care, nutrition, and a little love you should be able to enjoy your green iguana’s company for many years to come.
Green Iguana Habitat and History
The green iguana is native to the Americas where it has an extremely broad distribution. Green iguanas’ natural habitat ranges from Mexico to southern Brazil, Paraguay, and the Lesser Antilles. Humans introduced green iguanas to Hawaii and south Florida, too, where they enjoy the hot weather and plentiful foliage.
Green iguanas haven’t been changed through breeding as much as by their native geography. As far as looks go, iguanas have extreme variations and come in colors ranging from deep or muddy greens to light blues. Their crests and dewlaps can also vary in size, shape, and placement.
This article was verified and edited for accuracy by Dr. Adam Denish, VMD.