Green Iguana Care
       Susan Horton, DVM
       Green iguanas are very popular pets. They are perhaps one of the most misunderstood 
       and poorly kept of all reptile pets. They can reach considerable size. Recorded weights 
       and lengths of adult male iguanas have been as much as 20 pounds and 7 feet 
       respectively. Certainly not every iguana will become such a giant. But when considering 
       an iguana’s environmental needs, such size factors should be taken into account. They 
       also have specific temperature, humidity, lighting, and dietary needs. These topics will 
       be covered in this handout. At the end of this handout, a list of informative green iguana 
       books is provided.
       With daily handling, iguana (also called, “iggies”) hatchling and juveniles can be 
       transformed from flighty creatures into calm pets.  However, the power of this species 
       should never be underestimated once adulthood is reached!  These lizards are 
       relatively large in maturity and can cause severe injury if not properly handled and 
       respected with their tails, nails, and bites.  Iggies, although well tempered, are given up 
       frequently due to their size, habitat requirements, and their temperament.  This is at 
       least a 10 year commitment and a hefty financial investment as well. 
       Reptile rescues and local zoos are constantly asked to accept relinquished iguanas and
       most no longer accept these animals.  Please, consider adopting an adult or juvenile 
       from a reptile rescue.
       Natural History
       This New World species of lizard is found primarily in Mexico down to Brazil and has 
       been introduced toHawaii and South Florida where they are now considered nuisance 
       animals.  This species has also been introduced to the Lesser Antilles region where it 
       competes directly with the population of native iguanas.  Despite the iguana’s ability to 
       thrive and reproduce in introduced areas, this species is declining in native habitats due 
       to habitat destruction, their use as leather and food, and the pet trade.
       This is a long lived species averaging about 10-16 years with some living up to 25 
       years.  In captivity, they can thrive and grow from a hatchling to a large adult in 3-5 
       years.  It is well known now that this species requires optimal ultra violet radiation B 
       (UVB) exposure as well as high quality diets.
       Environment/Cages
       Keep in mind your cute little hatchling iguana will someday be much bigger. You may 
       start with a small 20-gallon aquarium now, but one day you will need a custom cage or 
       room dedicated to his reptilian needs. Surfaces of your chosen enclosure should be 
       smooth. Iguanas will rub their scales off their noses and hurt their feet if their enclosure 
       is made of wire. Wood may be used so long as it has been sealed with exterior 
       polyurethane varnish (such as marine varnish or similar). Allow the coating to cure for 
       several days and air it out well before inhabiting it. Molded plastic and acrylic cages 
       work well until the iguana out grows them. Iguanas should never be kept loose in the 
       house. There are to many dangers this way, such as animal attacks, accidental injuries, 
       and chilling.
       Your iguana will need branches to climb on. Chose branches of appropriate diameter 
       and strength to support his weight. Branches from outside can bring in pests. I suggest 
       either baking at 320 for 20 minutes or drying out over the outdoor gas grill for 30 
       minutes. Keep branch away from flames (for the obvious reasons). Choose hard wood 
       always. Pine and cedar will smoke heavily when baked! I usually use maple or oak.
       Security is especially important for small iguanas. For these little guys I suggest 
       covering half the exterior of the cage with paper or towels to provide a safe refuge from 
       perceived predators (i.e. you, the dog, the cat, etc). Eventually you can remove this 
       covering, once the little guy has acclimated to his new surroundings (6 months or so). 
       Silk plants may look nice in the cage, but most iguanas will eventually try to eat them. 
       They can be placed outside the cage instead.
       Bedding
       I recommend newspaper or outdoor carpet. Newspaper should be changed often. If you
       choose outdoor carpeting, have several pieces. This way you can be sanitizing one and 
       still have another to place in the cage. I do not recommend any particulate bedding, 
       (corncob, wood chips, wood shavings, etc.). It is swallowed easily by iguanas. Intestinal 
       blockage will lead to death if not addressed quickly. Particle bedding also hides a mess 
       well. The moisture from spilled water, feces and urine build up in particulate bedding 
       and will promote bacterial infections in your iguana.  Reproductive females will require a
       dig box to stimulate egg laying and prevent behavioral retention.  Dig boxes are 
       designated areas or enclosed sections of top soil that can go as much as 2 feet deep! 
       Temperature
       An iguana can not digest properly or have a competent immune system with out the 
       ideal heat. He is an ectotherm, which means he is the same temperature as his 
       surroundings. The preferred optimum temperature zone (POTZ) temperature for green 
       iguanas is 85°F to 95°F. The ideal nighttime temperature is 80°F-85°F. A gradient within 
       the enclosure is ideal. This way the iguana can heat up and cool down as his body 
       requires. Maintaining temperature is difficult. Most enclosures require a heating mat 
       applied outside the cage with a thermostat to maintain nighttime temperatures. For 
       basking, a reflector with appropriate wattage bulb will do. A branch should be provided 
       under the bulb. For iguana rooms, a space heater can be used. Build a protective 
       barrier around it so the iguana can’t get burned. Protect your iguana from burns by 
       using a thermometer to figure out the high and low temperature areas of your cage 
       before you place him in it. Never allow the iguana to touch the heat mat or bulb directly. 
       Severe burns will occur. Hot rocks are not appropriate. Your iguana is a basker, 
       meaning he gets his heat form basking in the sun. The hot rock will not heat the 
       enclosure and will promote burns and dehydration for your iguana. Do not place a glass 
       enclosure in direct sunlight. It will overheat and cook your lizard. Lights should go off at 
       night. I use timers on my lights.
       Humidity and water
       Iguanas should be provided with a large water bowl. I recommend a large lasagna pan 
       or cat litter box. It must be cleaned daily. Iguanas generally use their water bowl as a 
       toilet, thus requiring frequent changes. Humidity is difficult to maintain in most iguana 
       enclosures. Daily misting will help. Soaking in the bathtub weekly is also a good idea. 
       The tub should have warm water to iguana shoulder level. Allow him to soak for about 
       20 minutes. Never soak a weak or debilitated iguana without complete supervision. The 
       enclosure should never have condensation on the walls. This means you need more 
       ventilation or your cage is too wet. Skin infections often occur when the enclosure is 
       excessively moist. A hygrometer will read the ambient humidity. Iguanas need 65-75% 
       at least. Coming from the rainforests of South America , these lizards should ideally be 
       maintained at 80-95% relative humidity.  Humidity can be maintained with large water 
       bowls or bins, misting systems, foggers, humidifiers in large enclosures, and spraying 
       the enclosure 2-3 times a day.  
       Ultraviolet Radiation B
       This is a one of the key elements in keeping a healthy iguana.  Reptiles produce vitamin
       D in their skin through exposure to UVB radiation.  Vitamin D is important in calcium 
       metabolism.  UVB wavelength measures 290-320 nm. When purchasing a UVB source, 
       check to make sure it provides this wavelength.  There are several fluorescent bulbs to 
       choose from.  Repti-sun, Arcadia, and Zilla fluorescent bulbs or mercury vapor bulbs 
       produce adequate UVB.  The mercury vapor bulbs produce heat as well as UVB.  They 
       are very intense and penetrate 2 to 3 feet into an enclosure and up to 12 feet with 
       increased wattage. The amount of UVB will be diminished or blocked if it passes 
       through glass or plastic.  I recommend placing it on screen material.  The iguana should
       be no more than 12 inches from the fluorescent bulb.  Exposure time should be 8 to 10 
       hours daily.  Fluorescent bulbs need to be replaced every 6 to 9 months because the 
       UVB production stops about then.  I date my bulbs with a permanent marker to keep 
       track of replacement times. Mercury vapor bulbs last longer with some of them 
       producing UVB for up to 3 years.
       Nutrition
       This is another key to keeping healthy iguanas.  What you feed your iguana will 
       determine its lifespan.  Proper nutrition from the start will ensure healthy bones and 
       kidneys.  All food materials should be adequately washed, chopped and mixed.  Young 
       iguanas need their food finely chopped.  They may be fed twice daily.  As they age, 
       feeding frequency decreases to once a day, then every other day for adults (3 feet and 
       longer).  Ingredients for sub-adult meals should include items from these categories:
        1. Calcium rich vegetables: 40-50% of diet, 2 or more items per feeding-turnip 
          greens, mustard greens, beet greens, kale, collards, bok choy, Swiss chard, 
          dandelions, parsley, romaine, spinach, and escarole.  Spinach must not be over 
          used as it binds iodine and calcium.
        2. Other vegetables: 30-40% of diet, a variety weekly.  Frozen mixed vegetables, 
          squash, zucchini, sweet potato, bell pepper, broccoli, peas, beans, okra, carrot, 
          and pumpkin.
        3. Grain/fiber: up to 20% of diet.  Boiled rice, boiled pasta, whole grain breads and 
          cereals.
        4. Fruit: contain mostly fructose and fiber.  It dilutes more valuable nutrients in other
          food items, so minimize its use.  Figs, papaya, melon, apple, peaches, plums, 
          strawberries, tomatoes, banana (with skin), grapes, kiwi.
        5. Legumes: more important for young iguanas, up to 5% total diet. Boiled lentils, 
          navy beans, pinto beans, kidney beans.
       Adult Iguanas are primarily fed the calcium rich veggies with small amounts from the 
       rest of the list periodically. Senior Iguanas are primarily calcium rich greens.
       Vitamin supplementation is most important in to growing iguana.  A multivitamin 
       supplement should be used twice weekly.   Examples include Reptivite (Zoo-Med), 
       Reptical (Tetra), Nekton, and human Centrum.  A straight calcium supplement should be
       used 4 to 5 times weekly.  This supplement should contain no phosphorus and does not
       need vitamin D.  Iguanas seem to have difficulty absorbing vitamin D well from their 
       diets.
       * Older iguanas (adults) require a multivitamin once to twice monthly.  Calcium may be 
       given once weekly if male and three times weekly if female.
       It is an old industry practice to feed iguanas, especially very young ones, animal or 
       insect proteins to meet the dietary protein requirement.  The belief was that if an iguana 
       would eat the food then it must not be inappropriate.  This information is outdated and 
       has proven to be exceedingly harmful in many cases to this species.  Yes, in the wild an
       iguana may happen upon a few insects on their plants or ingest some carrion but this is 
       not the norm and is not done on a scheduled basis.  Do not feed iguanas insects, dog 
       food, cat food, or animal protein as this can lead to very serious and costly health issues
       in the future as well as death if uncorrected.
       Sanitation
       Cage cleaning should include thorough scrubbing and disinfecting. For washing, use 
       non-toxic soaps such as dish soap. Rinse well. For disinfection, dilute bleach (1:10) or 
       chlorhexadine. These must be rinsed very well. Allow cage to air out well before iguana 
       is returned. Daily removal of food is important.