Reptiles are cold-blooded creatures and need an external heat source. Reptiles in captivity also need sunlight. On this page, we will outline some of the basic necessities of captive reptilian care as pertains to heating and lighting enclosures. For further information on enclosures, visit Penelope's House.
Iguanas' natural habitat ranges from central South America (Peru) to southern North America (Mexico). As I'm sure you can guess, it doesn't get very cold during the year in this geographical range. Since iguanas cannot adapt like humans (or other animals) by adding layers of clothing or hair because they do not produce their own heat, they require external heat sources to maintain temperatures similar to those in their natural habitat. This is what Odysseus has to say about iguanas needing heat.
There should be a temperature gradient within the enclosure so your iguana can choose to sit in the heat or cool off. The only way an iguana can regulate its internal temperature is to move to an area where the ambient (surrounding) temperature is different.
The temperature gradient within the enclosure should range from 94° Fahrenheit on the warm side to 75° Fahrenheit on the cool side. This will give the iguana the opportunity to decide how warm it wants to be. Always be sure to regulate this temperature. If it is too hot or too cold, your iguana will suffer.
There has been great contoversy over the HOT ROCK issue in reptile circles. Hot rocks are not reliable heat sources because they do not provide ambient heat. If a reptile's enclosure is too cold, and the warmest spot is on top of the hot rock, serious burns can result. Reptiles cannot feel that a particular spot on their body is burning - they feel that their ambient temperature is too cool. Hot rocks are definitely not recommended for any reptile - for the same reason that the warning on a human heating pad label says not to lie on top of the heating pad.
Ceramic heating elements (CHEs) are probably the most widely used for heating the ambient temperature of reptile enclosures. Pearlco® is, in my opinion, the best manufacturer of CHEs. They come in different wattages, so you can select the one that will best provide heat for your iguana's enclosure. When using a CHE (or any heat source that fits into a light fixture), be sure to purchase a ceramic fixture. Plastic fixtures can melt and cause adverse effects (fire).
Another option for heating the enclosure is a red heat lamp. We use these currently in my enclosures. We have purchased ceramic wire-frame fixtures to house the lights (red, so the reptile cannot see them), and we have been very satisfied with their performance even during the coldest winter months here in Oregon.
Always be prepared for the worst. When the electricity goes out in your neighborhood, how will you provide heat to your iguanas? If you live in a rural area, a gasoline generator placed outside your house is effective. If you live in a more urban area where the constant noise of a generator would be unacceptable, consider your options.
Chemical heat packs will maintain heat for up to several hours if properly maintained. Styrofoam containers (such as coolers) with air holes provided, a heat pack wrapped in a towel and an iguana will be able to maintain their temperature for some time.
However, if your power is going to be out for more than a few hours, you will also have to consider other alternatives. Two years ago, our power went out for 10 days, and we did not have access to a generator until the last two days. Since we have propane for cooking purposes, it was relatively simple to cordon off the kitchen/living area with blankets (to maintain the heat in that area) and leave the oven on for a few hours at a time. We had a lot of turkey when the ordeal was over (it was an excellent excuse to bake turkey)! We also have a portable propane space heater that came in handy during that time. The space heater, however, is easily toppled by wandering iguanas, so it can only be used under direct supervision.
Since iguanas live in semi- to tropical climates, they have access to more direct sunlight all year round than the average captive iguana. When the temperatures are down to 55° Fahrenheit, you can't quite take your iguana outside to enjoy the benefits of natural sunlight.
There are several brands of artificial full-spectrum bulbs on the market today: Vitalite® and Reptisun® are two examples. Generally the lights come in different sizes from 18" to 48". Depending on the size of the enclosure, different size lights should be used. These lights tend to be effective from 12" to 18" from the basking site.
Flourescent bulbs behave differently than incandescent bulbs. They don't just stop working when the light becomes ineffective; rather, these lights can work for months after they stop producing UV light (necessary for processing Vitamin D3 which is necessary to process ingested calcium). The recommended life-span of a full-spectrum bulb is approximately 6 months. If, before the 6 months is up, you notice a blackish band near the ends of the light, it is time to replace your bulb.
As mentioned before, these full-spectrum lights are extremely important to reptiles. Without these lights, they are unable to process calcium which can result in several systemic problems including Metabolic Bone Disease (see the Feeding section for more info on MBD).
Of course, the best light for iguanas is natural sunlight. In the summer, if the weather is appropriate, an outdoor enclosure is recommended. Your iguana will be healthier and happier for this opportunity to bask in real sunlight (see the Housing section for info on enclosures).
As with heat in the enclosure, be sure to regulate the light as well. Iguanas are diurnal animals which means they are active during the daylight hours. A timer for your full-spectrum light is a necessity to maintain proper hours. If you have the light on erratically, this can cause stress in your iguana which can cause deterioration (lack of energy, loss of appetite, loss of color) which can eventually lead to systemic failures and death. An average diurnal schedule is 12-14 hours of light each day. We vary our light periods during the winter months to 11 hours and extend the light periods during summer months to 14 hours.
If you have any questions regarding the heating and lighting of your iguana enclosure, please feel free to contact us.