Internally-ballasted MV Bulbs: Pros Internally-ballasted MV Bulbs: Cons Heat & UVB in one fixture - convenient.
A bit more expensive than traditional tubes. Cost is usually around $45 each. Give off higher levels of UVB than tubes. Can produce too much heat when used in smaller enclosures - especially the spot bulbs. May enhance your iguana's green coloring and appetite (this is based solely on anecdotal evidence). Have a high burn-out rate. The bulbs are fragile and break if jostled. Bulbs are guaranteed, but returning broken bulbs can be a hassle. UVB travels further from the bulb, so they work better for larger enclosures and free-roaming iguanas.
The spot bulbs give off higher levels of UVB that travels a further distance, but the area covered by the bulb is less. Iguanas must stay directly under the bulbs. The flood bulbs cover a greater area. Externally-ballasted MV Bulbs: Pros Externally-ballasted MV Bulbs: Cons Longer-lasting with a lower failure rate than internally-ballasted MV bulbs.
More expensive than traditional tubes and internally-ballasted MV bulbs. Cost is usually around $75 each. Give off higher levels of UVB than tubes. Do not give off heat. A separate heat source is required. Can be used in smaller enclosures due to low heat output.
Not as widely available or as easy to find at this time as traditional tubes and internally-ballasted MV bulbs. Traditional Fluorescent Tubes: Pros Traditional Fluorescent Tubes: Cons A bit cheaper per bulb than MV bulbs.
Should be doubled-up for best results, thus bringing cost closer to that of interally-ballasted MV bulbs. Two tubes will usually cost around $30-$45. Can be used in smaller enclosures where an internally-ballasted MV bulb may produce too much heat. Produce much less UVB than MV bulbs. Plus, because fluorescent tubes do not produce heat, additional heat bulbs are necessary. Have a lower burn-out rate than internally-ballasted MV bulbs. Do not work well in cheap fluorescent fixtures. High-end fixtures are necessary for maximum UVB output. Come in different lengths to fit different enclosures.
The UVB does not travel far; thus it is necessary that the bulb is positioned no more than 12"-15" from the iguana.
Heat/Lighting - Iguanas need an enclosure or habitat that is kept very warm. Temperatures under basking lights should be in the low to middle 90's (Fahrenheit), and the ambient air temperature surrounding your iguana should be no lower than 80ºF. Within the cage, 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. Daytime heat is best provided with incandescent light bulbs.
Hot rocks are not recommended for iguanas! Not only are hot rocks inadequate in providing heat, but they are dangerous. There have been numerous cases of iguanas obtaining serious burns from hot rocks. Heat and light should come from above, since in the wild iguanas bask in the sunlight. Ordinary incandescent light bulbs work great to provide both heat and light. You do not need to purchase expensive "basking bulbs" from the pet store. These are no different than ordinary bulbs. What wattage of bulbs you will need depends upon the ambient air temperature of the room and the size of the enclosure or basking area. Do not guess when it comes to temperature! It is imperative that you install a few good, reliable thermometers at various places in the enclosure to give you an accurate temperature readout. You can also hook up dimmer switches to your lights, which will allow for minute temperature adjustment.
Hooded clamp fixtures work well for basking lights, come in a variety of sizes and can be positioned in various ways within an enclosure. Be sure to use fixtures that are designed to accommodate the bulb wattage you are using. If you are using high wattage bulbs (150-250W), you must use a fixture with a ceramic socket to prevent fire hazard. Be sure to place the fixtures in such a position that your iguana cannot climb on or touch them. If you place the fixtures inside the enclosure, it is a good idea to add a wire "bulb guard", such as you see in the photo below, to prevent your iguana from coming into direct contact with hot bulbs. Bulb guards can be made from hardware cloth or other safe types of wire. If you have a smaller iguana that is likely to climb up on and/or cling to the light fixtures, consider placing the fixtures outside of the enclosure.
This simple bulb guard was made from a small piece of hardware cloth, which is held in place by the simple guard that came with the fixture. The edges of the wire have been bent under so that no sharp edges are exposed.
Nighttime heat - Like all other animals, iguanas must have a day/night cycle. We recommend a 12:12 or a 13:11 cycle. This means that you must shut your iguana's lights off at night for 12 or 13 hours, or better yet, have them on a timer that turns them off at night and on again in the morning so you do not have to remember to do it. This allows the iguana to regulate behaviors and rest peacefully when necessary. Not providing a day/night light cycle can stress an iguana, causing behavioral changes such as feeding, pooping and unnecessary aggression. Iguanas can and should have cooler temperatures at night, but they still need ambient air temperatures to fall no lower than 75-78ºF. How then, do you provide heat at night, if you use light bulbs to heat the enclosure? There are a few methods of providing nighttime heat. One of the best is to use Ceramic Heat Emitters (CHEs), which screw into an incandescent light fixture and give off only heat, not light. These are available in different wattages. It is possible to have a set up where the lights come on in the morning and turn off at night, and the CHEs come on at night and turn off in the morning. Another possibility is to use a low wattage CHE 24 hours a day in addition to the daytime lights. Since iguanas can and should have cooler temperatures at night, a CHE of the appropriate wattage should provide adequate nighttime warmth.
A word of caution about CHEs - they get very hot and can be fire hazards and/or dangerous to your iguana if not used correctly. Be sure to use them only in fixtures with porcelain or ceramic sockets, and keep them away from dry wood or fabrics that are flammable. Be sure to place them in a way that will not allow your iguana to come in contact with them, because their surfaces get very hot and can cause severe burns. Use only the appropriate extension cords that can handle the amount of wattage you plan to plug into them. A CHE can be an efficient and safe source of heat for your iguana, but only if you use them properly. Be sure to read all of the directions and cautionary statements supplied by the manufacturer. Be safe, use your common sense, and above all, be careful - not only with CHEs, but with other heating and lighting devices as well.
In addition to CHEs, there are other methods of providing nighttime heat, such as letting your iguana sleep on a human heating pad wrapped in a soft towel. It can be dangerous to use heating pads for long time periods unsupervised, so CHEs are probably the better way to go.Some people use nighttime blue or red light bulbs to provide warmth at night. Some iguanas do not mind this at all, while others are bothered by the light and have trouble sleeping. You may want to watch your iguana carefully for signs of stress if you decide to try these nighttime bulbs.
In addition to these heating methods, many herp supply stores carry items such as "pig blankets", radiant heat panels, and heat tape, which may be appropriate nighttime heat sources for your iguana's enclosure. It is a good idea to explore all options to help you decide what will work the best for you.
UV Light - Iguanas require a source of UV radiation, specifically UVA and UVB. UVA is used by the iguana, just like humans, for a general sense of well-being. UVA is necessary to keep the Iguana happy and feeling good. UVA is easily supplied to your iguana through window glass or your standard room lighting. Providing a source of UVA like window exposure or room lighting will satisfy the UVA requirements for your iguana.
UVB is the tougher of the two to supply. There are many fallacies concerning UVB sources and it is very important that you know quite a bit about it and how it works. Being a diurnal creature (awake in the daytime), iguanas are basking reptiles that require a strong source of UVB (in a very specific range) in order to properly synthesize Vitamin-D, which allows them to absorb calcium from their digested foods. Without proper calcium metabolism, the iguana’s system will begin to use calcium from the bone structure in order to satisfy the requirements that keep their nervous system functioning properly. This leeching of calcium from the bones weakens them over time and causes a serious and often fatal set of illnesses including nutritional secondary hyperparathyroidism, fibrous osteodystrophy, rickets, osteomalacia, and metastatic mineralization, all relating to the common term Metabolic Bone Disease (MBD). To better understand the way UVB is used by your iguana, please read Calcium Metabolism in Iguanas by Dominick Giorgianni.
Remember - the absolute best source of UV light is the sun. When using natural sun exposure be sure to follow these guidelines:
The use of artificial UV bulbs or lamps in your iguana's basking area is strongly recommended - especially if you live in an area where your iguana cannot bask in the sun every day. UVB lamps are a hotly debated topic and the better educated you are, the better off your iguana will be. It is important to remember that not all UV lamps are created equal! In this regard the old adage, “Let the Buyer Beware” is very pertinent. Many ill-advised or unscrupulous companies will advertise that their lamps provide the proper levels of UVA and UVB for basking reptiles. While these lamps can provide a source of useable UVB, they vary greatly on the amount and how long it will last.
There are currently two types widely available of lamps that will emit enough UVB light to be beneficial to your iguana: Fluorescent tubes and Mercury Vapor lamps. Both of these types of UV lights can be purchased at pet stores and can be ordered from herpetological suppliers such as those listed on our Companies and Stores page.
By far the most widely used and accessible type of UV bulb or lamp is the fluorescent tube. Just like natural sunlight, these tubes need to be set up and used responsibly in order to provide your iguana with the life-sustaining amount of UVB it needs to live a long, happy and healthy life. Several brands of fluorescent UVB lights are available, but not all brands are of equal quality. The Green Iguana Society recommends the ZooMed Iguana Light 5.0 (also called Reptisun 5.0). This bulb has been on the market for some time and has been shown through studies to provide large enough amounts of UV light to keep your iguana healthy. We recommend that you mount two ZooMed 5.0 bulbs in a high-quality fluorescent fixture to get the best results. Ordinary "full-spectrum" fluorescent bulbs (such as plant-grow bulbs) do not produce adequate amounts UVB! Only bulbs especially made for reptiles do. When selecting a fluorescent lighting solution, please be sure to choose one that is specifically made for basking reptiles and all is rated for high UVB emissions.
There are several factors that are important to remember when setting up fluorescent lamps:
MERCURY VAPOR LAMPS
Mercury Vapor lamps (bulbs) are a newer way to provide your iguana with UVB rays. Mercury Vapor (MV) bulbs screw into an ordinary light fixture like an incandescent bulb. MV reptile lighting technology has advanced by leaps and bounds recently and is now a cost-effective, viable solution for an artificial UVB source, and in some cases is even better than fluorescents. MV lamps produce up to three-times more UVB in the 290-300 nanometer range (D-UV, the most beneficial to the iguana) of the total UVB output than tube-style bulbs. There has been great debate over the safety and usefulness of this type of lighting source. As the technology continues to advance, manufacturers are beginning to address safety concerns and stability and significantly decrease the “hazards” of mercury vapor lamp use.
It is important to realize that there are two types of MV bulbs: those with an internal ballast, and those with an external ballast. Although both give off high amounts of UVB, these two types of bulbs are actually quite different in their properties. The internally-ballasted bulbs are the type more commonly sold at pet stores and include brands such as Mega-Ray, T-Rex Spots and ZooMed Powersuns. Internally-ballasted MV bulbs give off heat as well as UVB. In this way they are convenient because you can provide your iguana with both heat and UVB from one bulb in one fixture. However, the internally-ballasted bulbs have a high failure rate, regardless of the bulb brand. Because the bulb gets so hot, the fragile filament breaks easily if the bulb is jiggled while it is on. The externally-ballasted bulbs are not as easy to find, but they are sturdier and have a much lower failure rate than the internally-ballasted bulbs. This is because they do not give off much heat, so the filament does not get as hot. In this way, the externally-ballasted MV bulbs are more similar to the traditional fluorescent tube, and therefore additional, separate heat bulbs must be used in the enclosure.
Based on current research, the Green Iguana Society strongly recommends the Mega-Ray MV bulb by Westron lighting/Mac Industries. Of the different types of mercury-vapor UVB bulbs available, the Mega-ray consistently gives off high amounts of UVB and has a lower UVB decay rate than other bulb brands. In addition, externally-ballasted Mega-rays are also available.
As with any lighting solution, there are several guidelines that must be followed when using any type of MV bulbs:
The charts below make comparisons between internally-ballasted MV bulbs, externally-ballasted MV bulbs, and traditional fluorescent UVB bulbs, with some pros and cons of each listed.
For more information on the pros and cons of mercury vapor bulbs, we encourage you to do some more research on your own. Visit Bob and Debbie MacCarger's article UVB Lighting and Heat for more detailed information about proper use of mercury-vapor bulbs. To find out more about some of the concerns about mercury-vapor bulbs, read Melissa Kaplan's article, Mercury Vapor Heat & UV Lamps. More information about Ultra Violet Radiation (UVA and UVB), heating and product use when applied to UVB-dependent basking reptiles can be found at Reptile UV Info. Another way to learn more about UV lighting is to subscribe to the UVB_Meter_Owners mailing list through Yahoo Groups. Ownership of a UVB Meter is not a prerequisite to joining this group. This group's members have a variety of species under their care, including Tortoises, Turtles, Iguanas, Bearded Dragons, Anoles, and other UVB requiring reptiles. UVA and UVC data are also discussed.
Humidity - Iguanas require high humidity as well as high temperatures. It can be difficult to keep the humidity levels in the enclosure at proper levels (between 65-75%). Ways to increase humidity include spritzing the cage and iguana with water several times a day, placing a humidifier in the room where the cage is located, and placing large tubs of water in the enclosure. You can also give your iguana a shower or bath every day to help with moisture availability. This is encouraged for a variety of reasons, including hygiene. (See more about bathing your iguana on our Bathing, Soaking and Misting page). An enclosure with plexiglass doors rather than screen would be superior in keeping humidity up, but precautions must be taken to ensure proper ventilation. Humidity levels that are too high can lead to mildew and fungus growth in the enclosure and on your iguana. Be sure not to spray the enclosure too close to the time the lights will turn off at night, because the moisture may sit for too long without the heat to evaporate it.
Another more sophisticated way of providing a humid habitat is to invest in a misting system or ultrasonic fogger. These products can and usually will be very expensive, but if used properly, they can create perfect humidity levels in your iguana's habitat. Most misting systems are equipped with timers that will allow it to briefly mist the habitat several times per day. Pro Products offers a high quality misting system as well as several other products, including radiant heat panels. Bush Herpetological Supplies also sells several different types of misting systems. Note: Although a misting system or ultrasonic fogger can create perfect humidity in your iguana's habitat, it can also create too much humidity which can lead to various problems. Such problems may include health risks for your iguana, an increase in bacteria, as well as quickly deteriorating an untreated habitat. Always monitor the humidity levels and always use these products according to the manufacturer's directions.
This photo shows one way to increase the humidity in an enclosure. An ordinary drier duct is attached over the outlet of a cool-mist humidifier with duct tape, and the mist from the humidifier then enters directly into the enclosure through the duct. This simple set-up raises the humidity in the enclosure by as much as 20%. Conclusion - There are a variety of enclosure designs that will be equally successful at providing your iguana with what it needs - proper heating, lighting, and humidity. What materials, design and heating/lighting devices you choose to use will depend upon the size of the enclosure or habitat, the placement of the enclosure, the surrounding room temperatures, and so on. For ideas on how to decide whether to build or buy, how to go about choosing the best building materials, and how to actually put it all together, visit our Building vs. Buying page, and the Planning and Construction page. If you have more than one iguana, visit our Multiple Iguanas page for a discussion on the pros and cons of housing two or more iguanas together. Thinking about building an outdoor cage? Check out the Outdoor Sunning Cages page.
Internally-ballasted MV Bulbs: Pros
Internally-ballasted MV Bulbs: Cons
Heat & UVB in one fixture - convenient.
A bit more expensive than traditional tubes. Cost is usually around $45 each.
Give off higher levels of UVB than tubes.
Can produce too much heat when used in smaller enclosures - especially the spot bulbs.
May enhance your iguana's green coloring and appetite (this is based solely on anecdotal evidence).
Have a high burn-out rate. The bulbs are fragile and break if jostled. Bulbs are guaranteed, but returning broken bulbs can be a hassle.
UVB travels further from the bulb, so they work better for larger enclosures and free-roaming iguanas.
The spot bulbs give off higher levels of UVB that travels a further distance, but the area covered by the bulb is less. Iguanas must stay directly under the bulbs. The flood bulbs cover a greater area.
Externally-ballasted MV Bulbs: Pros
Externally-ballasted MV Bulbs: Cons
Longer-lasting with a lower failure rate than internally-ballasted MV bulbs.
More expensive than traditional tubes and internally-ballasted MV bulbs. Cost is usually around $75 each.
Give off higher levels of UVB than tubes.
Do not give off heat. A separate heat source is required.
Can be used in smaller enclosures due to low heat output.
Not as widely available or as easy to find at this time as traditional tubes and internally-ballasted MV bulbs.
Traditional Fluorescent Tubes: Pros
Traditional Fluorescent Tubes: Cons
A bit cheaper per bulb than MV bulbs.
Should be doubled-up for best results, thus bringing cost closer to that of interally-ballasted MV bulbs. Two tubes will usually cost around $30-$45.
Can be used in smaller enclosures where an internally-ballasted MV bulb may produce too much heat.
Produce much less UVB than MV bulbs. Plus, because fluorescent tubes do not produce heat, additional heat bulbs are necessary.
Have a lower burn-out rate than internally-ballasted MV bulbs.
Do not work well in cheap fluorescent fixtures. High-end fixtures are necessary for maximum UVB output.
Come in different lengths to fit different enclosures.
The UVB does not travel far; thus it is necessary that the bulb is positioned no more than 12"-15" from the iguana.