Introduction: One thing that you will hear, over and over again, as you research iguana care, is that "iguanas are not easy care pets". Why is that? After all, other popular pets, such as dogs, cats, and fish, aren't nearly so difficult. What is it about iguanas that makes caring for them such hard work? Well, the biggest factor is this: iguanas, like other reptiles and amphibians, are dependent upon their environment for a wide variety of things that easier care pets such as mammals can get from other sources. They get heat from their environment. Their bodies use certain wavelengths of light in the environment to aid in their metabolism and body chemistry. They are very well adapted to their natural environment (warm, fairly humid places), which is usually extremely different from the captive environment in which they find themselves. What this means is that, unless you can create an environment for them that provides these things that they need, they will suffer, become ill, and maybe even die. Understanding your iguana's needs before you create a habitat for it is very important. Having said that, just what are an iguana's basic habitat needs?
Size: It is important for new iguana owners to realize that a properly cared for adult iguana will be LARGE - up to 6 feet long! Contrary to the common misconception, they are not limited in size by the size of their enclosure. They will continue to grow throughout their lifetimes – quickly at first, and then slowly as they age. A young iguana will outgrow a 55 gallon aquarium in its first year. Before purchasing an iguana, you must be sure you have the resources and space for a large enclosure, or the ability to provide your iguana with free roaming space that still provides all the habitat necessities.
An iguana enclosure should be at least twice the length of the iguana and should be tall. Six feet is the minimum habitat height recommended. Iguanas are arboreal (tree climbing) and feel most comfortable up high. The width of the cage should be at least half your iguana's length. The bigger the cage, the better off your iguana will be. Not only does an inadequately sized enclosure stress an iguana out, but iguanas that are kept in too-small cages injure themselves fighting the cage. Nose wounds and broken claws indicate that the iguana has been scratching at the cage walls or door or rubbing its nose along the glass or screen, trying to find a way out. Cages that are too small also limit the iguana's movement and climbing ability. Weakness in the muscles often results from lack of climbing exercise. If you cannot devote a lot of space to a large cage, or provide a lot of free roam space, then you need to consider getting a smaller pet.
A baby or juvenile iguana does not need a huge enclosure. In fact, a large aquarium makes a fine habitat for small iguanas. Be aware, however, that iguanas grow very quickly, and they will outgrow a large aquarium by the end of their first year. So, it is important that you plan ahead and have a large enclosure ready. In the meantime, the aquarium must have all the same things as the large enclosure: proper lighting, heating and humidity devices, and climbing materials.
The photo below illustrates the size difference between a hatchling iguana and an adult. With proper care, your iguana will reach adult size in as little as 2.5-3 years! Be sure to plan ahead!
Temperature: Since they are from the tropics and are cold-blooded, iguanas need an enclosure that is kept very warm. You must provide a basking spot that is 90-95ºF, and the ambient air temperature surrounding your iguana should be no lower than 80ºF during the day. Inadequately warm temperatures prevent iguanas from properly digesting their food and absorbing nutrients. Growth is stunted and malnutrition results. In addition, an iguana that is kept too cool will be uncomfortable and inactive. Within the habitat, a range of temperatures should be provided so that your iguana can regulate its body temperature by moving back and forth between cooler and warmer areas. Like all other animals, iguanas must have a day/night cycle. This means that you must provide heat at night without the use of lights. Many methods are available for doing so, and are discussed further in the Heating, Lighting and Humidity section.
Lighting: Iguanas must have a source of UVA and UVB light! UVA stimulates natural behaviors by providing a component of natural sunlight. UVB is important to iguanas for another reason. Without it, their bodies cannot manufacture vitamin D3 or properly metabolize calcium. Iguanas that are deprived of proper UV lighting suffer from a disease called Metabolic Bone Disease (MBD) which is unfortunately very common in captive iguanas. MBD causes weak bones, jaw and bone deformities and early death.
The absolute best source of UV light is the sun. Allowing your iguana to bask in the sun on a regular basis will provide it with large amounts of natural UV light. The general rule of thumb is - the more real sun your iguana has access to, the better. One thing to be aware of is that glass and plastic filter out the UV components of sunlight. It is for this reason that you cannot just set your iguana in front of a closed window in the sun. The window glass filters out most of the UV light, so your iguana will not benefit from such sunbathing in terms of vitamin D3 production (although he might enjoy this (in)activity immensely).
An additional source of UV light is special fluorescent UV bulbs available in pet stores that sell reptile supplies. Some people feel that if daily doses of real, unfiltered sunlight can be obtained on most days, then the use of artificial UV light bulbs in the iguana's enclosure is not necessary. However, The Green Iguana Society strongly recommends the use of artificial UV in addition to as much basking time in the sun as possible, to ensure that your iguana gets adequate amounts of UV. The effectiveness of real sunlight to stimulate iguanas to produce vitamin D3 varies with the time of year and latitude of your location. Therefore, the additional use of artificial UV lights acts as a safety net - especially in cool, cloudy and/or northern climates. See the Heating, Lighting and Humidity section for specific information on the proper use of UV bulbs in your iguana's enclosure.
Humidity: Iguanas require high humidity as well as high temperatures in their environments. One of the most common problems seen in captive iguanas is dehydration. Iguanas don't seem to be programmed to drink very much, perhaps because in their native rainforests there is sufficient humidity in the air and moisture in their food to keep them hydrated. Captive environments tend to be much drier, and with a lack of desire to drink, even if water is made available, many iguanas spend much of their time at least mildly dehydrated. Chronic dehydration taxes the kidneys, and can contribute to kidney failure at fairly young ages. For this reason, it is important to provide your iguana with a humid environment. High humidity also helps loosen shedding skin, which makes the shedding process easier and helps prevent retained shed. Humidity levels in your iguana's environment should be 65-75%. For ideas on how to provide humidity, see the Heating, Lighting and Humidity section.
Conclusion: As you can see, providing your iguana with the appropriate habitat conditions is quite a challenge. However, it is important to realize that it is necessary to do so. The items discussed above are not just what your iguana wants – they are what it needs to be healthy and happy. Once you are familiar with the conditions you need to provide, the next step is figuring out just how to do that. You'll need to decide on what type of climbing materials to provide, what type of floor covering, or substrate, to use, and what types of lighting and heating devices will work best for you. There are many options available, and not all are good choices. Some work well for some folks, but won't be compatible with your enclosure design. So, as far as learning about habitats, you aren't done yet! We encourage you to continue reading through our habitat section. Follow these links to find information about what types of habitat accessories you'll need, ways to provide heat, light and humidity, why building an enclosure may be better than buying one (Building vs. Buying), what materials you can use to build an enclosure and plans and suggestions for building (Planning and Construction), how and if to house two or more iguanas together (Multiple Iguanas), and tips on outdoor sunning cages.