The first important concept to be clear about before moving on to the lists of foods that iguanas eat is the correct ratio of calcium and phosphorus (Ca and P). Ideally, use vegetables that contain twice as much calcium as phosphorus (Ca:P ratio of 2:1), although a ratio of up to 1:1 (same amount of each mineral) is acceptable.
This ratio is very important for bone growth and maintenance, as well as for muscle contraction and many other body functions. The most common consequence of a poor diet is the development of the metabolic bone disease, which can be fatal if not corrected in time. The foods iguanas eat generally create a calcium-deficient diet, as very few vegetables maintain the ideal 2:1 ratio. When selecting the ingredients of the diet, use vegetables that contain at least 1:1. We will give you a list of vegetables ordered from highest to lowest in terms of their calcium content, but they should always be combined with others that contain less to avoid excesses.
On the other hand, you should also take into account the protein content of the vegetables that the iguanas eat. The group that contains the most is that of legumes, so include some always in the diet.
Oxalic are plants that contain oxalic acid, which combines with calcium and does not allow the body to absorb it. Vegetables from this group are spinach, rhubarb (considered toxic and should be avoided), beets, beet leaves, celery sticks, and chard. As you will see these contain a lot of calcium, but it is useless when combined with oxalic acid, so try not to use them or use them only in small amounts.
Other vegetables that eat the iguanas but should not be used in excess are cabbages in general, as they can cause thyroid problems. These include cabbage, kale, Chinese cabbage, broccoli, turnip, swede, cauliflower, and Brussels sprouts. You don’t have to avoid them, just limit the amount or give them occasionally.
Finally, another group of vegetables that should not be given too much is that which contains tannin. This pigment binds to enzyme proteins, preventing digestion, and also renders iron and vitamin B12 useless. If too much is given, it can damage the liver. Vegetables that iguanas eat that contain a lot of tannins are spinach, carrots, bananas, grapes, lettuce, rhubarb (toxic to iguanas, should be avoided completely) and onions.
Good vegetables for iguanas, which have no contraindications and are nutritious, are cabbage leaves (Galician cabbage), turnip leaves, mustard leaves, parsley, dandelion leaves, rapini, green beans, figs (fresh or dried), green peppers, endive, raspberries, leek, peas, blackberry, grapes, radish, okra, peas, prickly pears (cactus fruit) and parsnip.
Now, you must remember to offer a variety of at least 10 different ingredients, it is not enough to take two or three from this group and feed them to your iguana. You can use other vegetables with good nutritional value that are not on this list, but avoid those mentioned as dangerous. You can take the ones on the list as basic choices for your diet, but include more by taking into account their nutritional value, their price, the tastes of your iguana and the availability in the area where you live.
For a long time, it was recommended that growing iguanas be given a higher protein diet, such as a dog or cat food. Nowadays it is known that both adults and young iguanas are strictly vegetarian and their diet is the same. It is advisable to give them a vitamin and calcium supplement.
These diets are very recent and have not yet been tested enough to know if they are good. Some iguanas that are fed exclusively on these diets have developed dietary deficiencies within the year. There is still notable of the iguanas’ nutritional requirements, so no manufacturer can claim to meet these needs. Combining the feed iguanas eat with a good variety of vegetables is the safest way to achieve a complete and balanced diet. You can also use the feed for travel, when you have no other supplies or when someone else is in charge of your iguana.
Some iguanas love junk food and will be delighted if they can get hold of a piece of pizza or some ice cream. If they only do it occasionally, it won’t hurt them at all. It’s like when children eat sweets, which have no nutritional value but are tasty and make them feel good. Just as you would with your children, don’t let this kind of food make up a large part of the food that iguanas eat in their diet.
Despite the efforts you make to balance an iguana’s diet, it is always advisable to sprinkle some of these supplements on top of its ration to avoid deficiencies. For young iguanas, you can use only a little bit one day a week and for adults twice a week, but don’t overdo it. You can use a human multivitamin and grind up the tablets.
For calcium, look for a formula that contains only calcium and vitamin D3, without phosphorus. Remember that most of the vegetables that the iguanas eat have more phosphorus than calcium and you have to try to counteract this imbalance. To know how much to give, try to estimate how much calcium is in the diet you are preparing using the list of calcium content in the vegetables as a guide. If you’re using the 2:1 or higher, you won’t need to supplement, but if you’re using the lower calcium, then add a supplement or change the formulation.
Finally, you should know that iguanas tend to eat more in the summer and gradually lose their appetite towards the winter. Also, autumn is their breeding season and they may stop eating because of this.
The amount of food to be provided depends on the size of the iguana. Simply give them as much as they can eat, as they do not overfeed. After studying it for a few days, any owner will be able to know what the appropriate size is. Once it has finished eating, you should remove the excess to avoid spoiling it and to keep the cage clean. Also, this way you can get used to eating at a certain time.
The best time to feed the iguanas is in the morning, between half an hour and an hour after they wake up. This way they have all day with higher temperatures to digest what they have eaten. You can go back to eating during the day if you like, but the bulk of the food should be given in the morning. I recommend that you always feed them at the same time so that he defecates regularly. This is useful if you want to teach him how to use a tray or to clean up right away so that the stool does not stay in the cage for long.
The plate can be made of ceramic, plastic, or glass, it should be flat and large because iguanas like to climb up to dig into their food. Any material you choose should be well washable and if it is heavy, better so that it cannot be knocked over. It is advisable to place the plate on top of the cage so that it does not accidentally swallow substrate or come into contact with the food.
As for water dishes, it is better to have more than one. Usually, a large one is placed at the bottom of the cage for them to soak in, and they will almost always use it to defecate. It is therefore convenient to put a smaller one, so that you cannot enter it, somewhere elevated, in case you want to drink. The water dishes also serve to keep the environment humid, as the liquid evaporates due to the high temperatures of the enclosure.
Finally, you must remember that an important part of a good diet for an iguana is an adequate source of UV radiation. Thanks to UV rays, the body can form enough vitamin D3 to absorb calcium from the food. The best source of this radiation is unfiltered sunlight, so it is good to have a cage outside so that the iguana can get at least one hour of sunshine every day. If you can’t, use good quality tubes as an artificial source.
If after reading this article you have decided to keep an iguana as a pet, here are two more that may interest and help you: