The green iguana is one of the more popular pet lizards for experienced keepers.
In my April 2013 REPTILES article, Blessed Be the Bearded Dragon,” I wrote how the green iguana was the king of the pet lizard world until its title was eventually usurped by the bearded dragon, now arguably the most popular lizard in the pet trade. It’s true, but don’t write off the green iguana just yet. This regal lizard is still a favorite pet with legions of devotees. The trick to keeping a green iguana successfully is to know ahead of time what to expect and to be prepared to meet this lizard’s demanding care requirements. If you do, you may find yourself with an lizard companion that could live for up to 20 years.
Green iguanas will always hold a special place in my heart, due to Yombo, my pet green iguana that I had for many years. When I first began working for REPTILES nearly 20 years ago, I would sometimes bring him to the office, where he would elicit oohs and ahhs (not that he seemed to care). He was also one of REPTILES’ first "models,” in that he was the subject of some of the first photo shoots the magazine ever had. He was very laid-back most of the time and always tolerated handling well. That said, he wasn’t above giving me an occasional thump with his tail if he was feeling irritable. Good ‘ol Yombo—he was an excellent green iguana ambassador.
The Iguana Boom
The green iguana (Iguana iguana) is a very impressive lizard, indeed. It inhabits tropical environments in the Caribbean, Central and South America. It is arboreal and herbivorous, and some adult males can reach lengths of 6 feet, much of which is long, strong tail. Both sexes have a dewlap and spines down their backs, though these are much more prominent in males. The spines on a male can be so long, that they flop over to one side. Males also possess heavier jowls, and the prominent sub-tympanic shields (the large, circular scale on each side of the head) are also larger in males than females.
The normal coloration of the green iguana is—surprise!—varying shades of green, though some exhibit a lot of orange coloration, too. Also, thanks to captive-breeding efforts, you can find green iguanas that exhibit other colors, including blue, red, white and yellow. The price tag for these other color types is higher than for a normal green iguana, but they certainly are eye-catching lizards!
Due to its looks and mostly mellow personality, the green iguana has been a staple on the pet scene for many decades, but it became über-popular after the movie Jurassic Park began thrilling moviegoers in 1993. After that, larger numbers of iguanas than ever before were sold to people who wanted the closest thing they could get to a pet dinosaur. You have to admit, with its impressive head, hefty dewlap and large spines, an adult male iguana certainly looks prehistoric. Iguana farms sprang up in Latin America to meet the huge demand for pets, and cute, baby green iguanas by the thousands made their way to U.S. pet stores. It was a bona fide iguana boom! Unfortunately, many enthusiastic, would-be iguana keepers, who bought baby iguanas cheaply and on impulse, found out the hard way that they were unable to provide their new pets with the care they needed to thrive. Many baby iguanas perished, and large adults became increasingly common in shelters and rescues.
Happily, in the years since, reptile hobbyists have become much more enlightened when it comes to the proper care of a green iguana, and this impressive lizard remains a favorite.
How to Choose a Green Iguana
It is not hard to find green iguanas for sale. Hatchlings and subadults are commonly available at pet stores and reptile expos, and the latter are often the best places to see firsthand some of the more unusually colored iguanas. The benefit to buying an iguana at a store or expo, of course, is that you can personally inspect your potential new pet. You can buy green iguanas online, too, but because you will not be able to examine the lizard in person, try to find websites that are run by reputable breeders/dealers whenever possible. See if they have customer references or testimonials, and ask if they sell their animals with any type of guarantee.
When examining a potential pet iguana, look for eyes that are bright and unclouded. The skin around them should be healthy-looking, not dark and sunken. Check the wrinkles around the eyes for signs of mites.
An iguana’s jaws should be firm and straight, with the upper and lower jaws meeting properly. They should not be malformed in any way, as this could be a sign of nutritional secondary hyperparathyroidism (also known as metabolic bone disease, MBD, or "rubber jaw”). The tail, legs and back should be straight and normal, without any kinks or deformities. Be sure the iguana can walk properly.
Check that the base of the tail, where it meets the body, is full and thick. It should not be sunken on the sides, as this is where a well-fed iguana stores fat reserves. If this area is scrawny, the iguana may not be eating.
Examine the vent area to ensure it’s clean, and inspect the entire body top to bottom for skin abnormalities, such as missing scales, mites, lesions, lumps and bumps or any signs of injury. Look at the toes and toenails; are they all there? Are any broken?
Sometimes people want to take an unhealthy animal home, thinking they will bring it back to good health. This is noble, but doing so can result in problems. You could end up having to spend a lot of money on veterinarian bills. Or the animal may never recover from whatever was ailing it. It is always recommended, therefore, that hobbyists start out with a healthy animal to ensure the best reptile-keeping experience possible.
The Best Green Iguana Enclosure
Naturally, a lizard that can grow to nearly 6 feet in length is going to need a very large enclosure. The theory that an animal will "stunt” to the size of its enclosure and not outgrow it is a myth. You can keep a hatchling green iguana in a 20-gallon aquarium for a while, but it will eventually need a much larger enclosure. A common recommendation is to provide a cage that is at least twice as long as the length of the lizard. So for an adult iguana, you could eventually be looking at a 12-foot-long enclosure.
Because green iguanas are highly arboreal—they like to get as high up as they can, which helps them feel secure—a cage that is 6 feet tall would be ideal for sub-adults and adults. The width should be at least as wide as the lizard is long.
With enclosures of these dimensions, unless you have a spare room you can set up for your iguana, you’re going to need to build a custom cage, or have one built for you. Wood and screening can be used to good effect, as screened or partially screened enclosures are a necessity in order to allow crucial UVB light to get to your iguana (more on that later). They also help with ventilation, because although you want a humid environment, you don’t want to encourage mustiness and mold.
Iguanas sneeze out excess salts, a normal byproduct of digestion. If glass or Plexiglas walls are used in an iguana enclosure, they will often be spattered with residue and need frequent cleaning for optimum viewing pleasure. The residue an iguana expels while sneezing is sometimes called "snalt”—I think you can figure out which two words were combined to come up with that one!
Provide plenty of sturdy branches, perches or shelves for your iguana to climb and rest upon, at varying heights within the enclosure. Use screws, wire, brackets and whatever else may be necessary to ensure they’re attached securely within the enclosure, and that they will support the weight of a heavy lizard. Adult iguanas can weigh up to 20 pounds.
Plants can be placed in an iguana enclosure, though they could take a beating. Iguanas are herbivores, too, so the plants could take both a beating and an eating! Artificial plants are an option; just be sure they’re sturdy and not easy to tear apart should a curious iguana attempt to snack on them. You don’t want to risk your pet ending up with an intestinal impaction.
Palms, ficus, hibiscus and other live plants can be used to create an eye-catching enclosure that your iguana is sure to appreciate. Just be sure to avoid toxic plants (consult a nursery; also, a toxic plant list can be found at ReptileChannel.com/toxicplants). The potting soil in pots containing store-bought plants could contain fertilizers or pesticides that might be harmful to your iguana. Therefore, use untreated soil to re-pot plants you want to place in the enclosure.
Moisture-retaining substrates such as cypress mulch work well with green iguanas. Newspaper can be used, too, thought it’s not as attractive and doesn’t help with humidity. It’s simple and cheap to replace, though, and iguanas can be a tad on the messy side. Alfalfa/rabbit pellets are sometimes used and generally are safe if eaten, though they can get gross if they get wet or soiled. Replace them as needed.
Green Iguana Heating and Lighting Tips
Iguanas are very much diurnal basking lizards and ultraviolet light, both UVA and UVB, is crucial to maintaining a healthy pet. The use of some kind of UV-emitting light is mandatory if you plan to keep your iguana indoors. Iguanas need them in order to process calcium, and without UV they could suffer ill health, especially the previously mentioned nutritional secondary hyperparathyroidism. Green iguanas, sadly, seem especially prone to this condition if their needs are not met.
Pet stores carry a variety of full-spectrum UV bulbs for reptiles, ranging from fluorescent tubes that provide UV light only to mercury vapor lamps that provide both heat and UV. If you go with the tubes, keep in mind that their UV-providing properties can diminish over time even though they may still emit light. Be sure to follow manufacturer recommendations for when it is time to replace the bulb.
Glass filters out UV rays, so don’t position lights over any kind of glass; they need unobstructed access to your lizard. As a matter of fact, because their efficacy decreases with distance, UV-emitting tubes should be positioned so your basking iguana is fairly close to them. Ideally, this would be about 7 inches above your iguana’s favorite basking spot. Mercury vapor bulbs are more powerful and having them too close to your pet might result in a burn, so again, check manufacturers’ recommendations and proceed accordingly.
A typical day/night light cycle of 12-hours-on, 12-hours-off can be maintained easily by using timers. Nighttime temps can drop to the high-70s; use nighttime bulbs or non-light-emitting heaters (such as infrared elements) to maintain them, if necessary.
During the day, provide a basking hotspot of about 100 to 120 degrees Fahrenheit, using an overhead heat source, such as an incandescent lamp or mercury vapor bulb in a dome fixture, or an infra-red heating element. Some include built-in thermostats, which can remove some of the guesswork. Overhead heat sources are best for iguanas, as opposed to devices that heat from below, such as heat mats. Hot rocks are definitely not recommended for green iguanas. Be sure your lizard cannot come into contact with any heating elements; either place them outside the enclosure (assuming it has a screen top or walls) or, if you must put them inside, use wire guards or cages to prevent contact with your green iguana.
Concentrating heat in the upper regions of the enclosure will provide a vertical temperature gradient along which your iguana will position itself to feel comfortable. Cooler temperatures toward the lower areas should be in the 80-degrees range during the day. Thermometers in both the upper and lower regions will help you keep track of temps.
Try to maintain a humidity level of about 70 percent. To help achieve this, either mist the enclosure manually using a spray bottle daily, or consider setting up an automatic misting system on a timer. Standing water bowls or a soaking tub can also help raise humidity. To maintain humidity within screened cages, you may need to experiment with covering portions of the screening with plastic—though you also want to avoid severely affecting ventilation by doing so. Use a hygrometer to help you keep track of the humidity level.
What do Green Iguanas Eat?
I remember a photo in REPTILES years ago that showed a hatchling green iguana eating a cricket. Even though at the time some people considered it okay for hatchling iguanas to eat small amounts of animal protein, some people went ballistic over it. Animal protein, whether in the form of insects, pinkies or other items, is not recommended for iguanas, hatchling or otherwise. They are strict herbivores, and feeding them animal protein can lead to health problems, including kidney failure.
The primary foods you should offer your iguanas are dark, leafy greens, such as collard, mustard and dandelion greens, all of which can be found in most grocery stores. These should make up about 50-percent of your green iguana’s diet.
Most of the remaining 50 percent can be other vegetables, such as sweet potatoes, squashes (including butternut and yellow), green beans, carrots, zucchini and bell peppers (all colors). Fruit such as mango, different types of melon, papaya, banana, strawberries and other berries, etc., can be offered, but only in small amounts, as fruit can cause diarrhea. Acidic fruits, such as oranges, grapefruit and tomatoes, can also be offered, though they may not be accepted as readily as other fruits.
Beware certain vegetables, such as spinach, Swiss chard and kale that contain oxalates; these can prevent your iguana’s body from processing calcium. Offer them only rarely, if at all. Some people feed their iguanas dog or cat food, or monkey biscuits, but these contain animal proteins and should be avoided.
Iguanas like flowers—many keepers offer hibiscus flowers—but if you want to give them to your iguana you must be positive the flowers have not come in contact with any kind of pesticide or other dangerous chemicals. If you’re not absolutely sure, don’t do it.
Daily iguana salads comprised of the above foods will be relished by your pets. Chop them up finely if you’re feeding hatchling iguanas. There are also commercial iguana foods available at many pet stores; the ones with high fiber and no animal protein (though plant proteins are OK) are considered the healthiest. Offer food in a bowl to lessen the chance that your iguana will ingest substrate along with it. A couple times a week, sprinkle powdered calcium supplement on the salad, according to manufacturer recommendations.
Water can be provided in a bowl, or a larger tub that your iguana may enjoy soaking (and going to the bathroom) in. Having some type of standing water in the enclosure can also help raise the humidity, but be sure dirty water is replaced quickly and use a bowl that will not tip over. Iguanas get a fair amount of water from the foods they eat, too, but you can ensure yours is getting plenty by spraying its salad lightly with water prior to feeding.
These are the basics of green iguana care, and you can see it’s not as simple as placing a hatchling into an aquarium and feeding it lettuce. There’s much more to it than that. Green iguanas, even hatchlings, are not recommended for children or beginners. But if you work your way up to an iguana and gain the proper experience and are able to make a major commitment, you could end up keeping an awesome pet lizard! REPTILES
RUSS CASE is the editor of REPTILES magazine and ReptileChannel.com. He has written three children’s books about reptiles—Lizards (2006), Turtles and Tortoises (2007) and Snakes (2007)—and can often be found interacting with readers and giving things away (including free subscriptions to REPTILES) on REPTILES’ Facebook page at www.facebook.com/reptilesmagazine.