An improper diet contributes to a wide variety of health problems in iguanas, some of which may be life-threatening. Over the past 20 years, veterinarians have learned a lot about proper nutrition for reptiles, so the recommended diet for pet iguanas has changed a great deal.
What should iguanas eat?
Iguanas are herbivorous, meaning they eat plants; specifically, they are folivores, meaning they eat leaves. In the wild, iguanas feed almost entirely on the leaves of trees and vines, plus some fruits and flowers.
Iguanas are hindgut fermenters, which means they have specific microbes (special bacteria and flagellate organisms) in their gastrointestinal tracts that ferment the high-fiber foods they ingest, so the iguana can absorb and use the nutrients in these foods.
While most veterinarians recommend feeding only plant material to iguanas, many others feel that supplementing the total diet up to 5%-10% with commercial canned or pelleted food formulated specifically for iguanas is acceptable.
How often should I feed my iguana?
Most young iguanas need to eat daily, while adult iguanas can be fed daily or every other day. If your iguana is overweight, feeding every other day or every third day may be sufficient.
What types of plant material can I feed my iguana?
Most of the diet (80%-90%) should be dark green leafy vegetables, with less than 20% of the diet fruit. Yellow, red, and orange vegetables also can be offered. Avoid nutrient- and vitamin-deficient light green vegetables, including celery and iceberg or head lettuce, as these vegetables contain mostly water and very few nutrients.
Calcium-rich vegetables that are best for feeding iguanas include collard greens, beet greens, mustard greens, turnip greens, alfalfa hay, bok choy, kale, parsley, Swiss chard, romaine, kohlrabi, escarole, and dandelion. These vegetables should compose 40%-50% of an adult iguana’s diet. Other vegetables can make up an additional 30%-40% of an adult iguana’s diet, including cactus, broccoli, squash, bell peppers, green beans, sprouts, sweet potato, parsnips, okra, cucumber, asparagus, mushrooms, carrots, peas, and corn.
While Swiss chard, spinach, and beet greens are a great source of calcium, they should not be fed exclusively. These plants prevent absorption of dietary calcium and trace minerals in the intestine, potentially leading to nutrient deficiencies. In addition, cabbage, kale, and mustard greens contain goitrogens, which are chemicals that can lead to goiter, or hypothyroidism, in which the thyroid gland becomes enlarged and functions improperly. For these reasons, these vegetables should be fed only in small amounts.
"Fruit should comprise only a small percentage (less than 20%) of an iguana’s total diet."
Fruit should comprise only a small percentage (less than 20%) of an iguana’s total diet. Fruits that may be offered to iguanas include apples, pears, bananas (with skin), mangoes, grapes, star fruit, peaches, tomatoes, guava, kiwis, melons, figs, apricots, dates, blueberries, raspberries, and strawberries. Iguanas love fruit, but most fruit is water-rich and nutrient-poor, so these items should be fed sparingly, and only as a top dressing on the vegetables.
As a treat, edible flowers may also be offered to iguanas, such as geraniums, carnations, dandelions, hibiscus, nasturtiums, and roses. Also, young, growing iguanas also may be fed legumes, including boiled lentils, navy beans, pinto beans, and kidney beans. These food items should never be more than 5% of their total diet.
Vegetables can be offered cooked or raw, although raw is preferable, since cooking removes many essential nutrients. Thoroughly wash all fruits and vegetables to remove debris and pesticides before feeding them. If available, organic produce, grown without pesticides or other potentially toxic chemicals, is best to feed to your pet iguana. Edible flowers can be homegrown or purchased from floral shops. Often, floral shops throw out older, wilting flowers that iguana owners can get at no charge. Be sure that no chemicals have been applied to the flowers before feeding them to your iguana.
Are animal-based protein foods appropriate for my iguana?
Foods that include large amounts of animal-based protein, such as crickets, mealworms, pinky mice, tofu, and hard-boiled eggs, are generally too high in protein for iguanas to eat frequently and should be offered as less than 5% of the adult iguana’s total diet. Young, growing iguanas can have up to 10% of their total diet made up of animal-based protein sources. Do not feed dog and cat food to iguanas, as it contains too much protein, vitamin D, phosphorus, and fat.
Do I need to give my iguana vitamin and mineral supplements?
The amount and type of supplements iguanas require is controversial and somewhat age dependent. All iguanas, regardless of their age, have a higher requirement for dietary calcium than for phosphorus. Check with your veterinarian for specific recommendations for supplementing your pet iguana's diet.
Young and Growing Iguanas
Most veterinarians recommend lightly sprinkling a growing iguana’s food with calcium powder specifically formulated for reptiles (calcium carbonate or gluconate) every other day (4–5 times per week). These calcium supplements should be phosphorus-free and without added vitamin D.
Young, growing iguanas need vitamin D to form their bones properly, and many are housed inside, with minimal UV light exposure, so most veterinarians recommend that young iguanas receive a multivitamin supplement containing vitamin D, twice a week, even though there is some controversy about whether iguanas can absorb vitamin D from their food (they may only be able to use the specific form of vitamin D made in their skin in response to UV light).
Adult Iguanas
Most veterinarians recommend that fully grown, adult iguanas be given a calcium supplement lightly sprinkled on their food, once to twice per week, and a multivitamin containing vitamin D twice a month. Any supplements should be dusted onto small portions of salads or moist foods, and those portions fed first to ensure that the iguana receives them.
Does my iguana need water?
Fresh, clean water should always be available for your iguana. Iguanas will not only drink from the water bowl, but also bathe in it. Since reptiles absorb water through their skin, both drinking and bathing help keep iguanas hydrated. Provide water in a heavy bowl that is not easy to tip over. Change the water and clean the bowl daily, as iguanas will often eliminate in their water bowl while bathing. You should also mist your iguana with a water sprayer a few times a week to help keep them hydrated, especially during the winter when the air is colder and drier.
Opinions vary regarding the nutritional needs of captive iguanas, and our knowledge in the subject is continually expanding based on new dietary studies in reptiles. Therefore, if you have a pet iguana, you should discuss your pet’s specific nutritional needs with your veterinarian at each wellness visit or annual examination.
