Iguanas come from hot, humid areas of Mexico, Central and South America. Many places north of Mexico are relatively cool and arid. The high relative humidity is good for your iguana's skin, but it has proven difficult to effectively maintain high-humidity environments for captive iguanas. Not only can it be tricky to raise the humidity to the proper level (iguanas feel right at home when the humidity level reaches 85-95%) but it is difficult to keep such enclosures clean. Hot, humid areas are succeptible to bacterial growth, and with food and feces in such close quarters, the humidity can prove to be dangerous. Subsequently, most iguanas are kept in environments that have low relative humidity, and seem to suffer no adverse effects except perhaps dry skin. This condition may be evident by the appearance and feel of the spines along your iguana's back. When the humidity is high, shedding is accomplished easily, and the dead layer of skin on the spines can be pulled right off without any problem. When the skin is dry, the spines often appear white (due to the dead skin) for long periods of time, and the skin on the scales sometimes comes off in part rather than in whole. Still, this does not seem to be detrimental to iguanas in captivity, and the dry skin condition is preferable to bacterial growth!
If you do wish to try to raise the relative humidity in your iguana's enclosure, there are a couple ways of doing so. If your iguana has a large enclosure, you can simply purchase a humidifier to add moisture to the air. If your iguana lives in a smaller cage, you can add humidity in a few different ways. You can either use a spray bottle to mist the iguana and the cage once or twice a day, or you can place a large bowl full of water in the cage which will evaporate and raise the humidity level. If you choose the water bowl method, you may wish to place a heat lamp above it to speed up evaporation, or placing an under-tank heater underneath that area will create the same effect. To help your iguana with its shedding, you may also soak it in warm water. You can gently rub your iguana's skin to help remove dead skin, but never pull off any skin that is still "stuck" on.
By Melissa Kaplan