Ultraviolet (UV) Light Information for Reptiles and Amphibians

Ultraviolet (UV) lighting is critical for many species of reptiles. Unfortunately many new reptile owners are confused by what kind of bulbs provide ultraviolet (UV) light and whether it is the right kind of ultraviolet light. This article will hopefully answer many questions about ultraviolet (UV) light and bulbs.

Ultraviolet (UV) light is not visible by people but it is a vital part of natural sunlight, just like infrared light. Ultraviolet (UV) has three wavelengths referred to as UVA, UVB, and UVC. In herpetology and herpetoculture only UVA and UVB are usually mentioned.

UVA is the type of ultraviolet light visible to reptiles and amphibians. UVA will help induce natural behaviors in diurnal reptiles and amphibians like feeding, breeding and is good for their overall well being.

UVB is the type of ultraviolet light that is not visible. UVB is what helps some reptiles manufacture vitamin D3. UVB is also the type of ultraviolet that gives us humans sunburns. Vitamin D3 is necessary for amphibians and reptiles to metabolize the calcium in their diet. Without vitamin D3 they are unable to use the calcium. Even if they are offered daily calcium supplements, they could still suffer from Metabolic Bone Disease (MBD). Reptiles and amphibians, unlike humans, cannot make their own vitamin D3 and require UVB light.

UVC is the third wavelength of ultraviolet light. It is extremely dangerous and can alter DNA. It is most often used in UV Sterilizers found in the aquarium and water gardening hobbies to kill algae and bacteria.

Not all reptiles and amphibians need ultraviolet (UV) light. Nocturnal species like leopard geckos do not require ultraviolet (UV) light in captivity because they are only active at night and never receive ultraviolet (UV) light. Most experts agree that snakes and similar predatory species like monitors do not need ultraviolet (UV) light since they obtain all of the vitamin D3 they need from their prey items.

Just about all diurnal reptiles and amphibians (with the exception of snakes and some others) require UVB light. This includes green iguanas, bearded dragons, African spur thigh tortoises, and many many more. Reptiles and amphibians found in the tropics or desert require even more UVB light than other species because of the areas they come from.There are light bulbs specifically made for these species. Without UVB light these reptiles and amphibians suffer metabolic disorders and softening of their bones that will eventually lead to a slow and premature death. The specialized lighting required to keep many reptiles and amphibians is one of the reasons that many inexpensive lizards, like the green anole are not neccesarily the best reptile to start with for new hobbyists.

There are many ways of providing UVB light to your reptiles and amphibians. Some of the easily accessable commercial products include fluorescent tubes, fluorescent power compact bulbs, mercury vapor bulbs and natural sublight. One fact that many people do not realize is that glass and plexi-glass filter almost all ultraviolet (UV) light. Even fine screen and mesh can greatly reduce the amount of ultraviolet (UV) light that a reptile or amphibian receives. Simply placing your reptile's enclosure near a window or even having a UVB producing bulb on top of a screen top is not providing enough UVB light to be benificial. Whenevever possible you need to try and have no obstructions between the reptile and and UVB light source.

Fluorescent light bulbs that provide UVA and UVB light have been around for many years in the pet industry and reliable. They are often some of the least expensive bulbs available and can do a passable job. Not all bulbs that are marketed as ultraviolet are created the same. There are many greate manufactures like Zoo Med and Exo-Terra that make excellent fluorescent bulbs suitable for reptles. Stay away from "black lights" or plant grow lights that you can find in hardware stores since they generally do not provide enough, if any, UVB light and are not appropriate for exclusive use with animals that require UVB light. These bulbs can be used in enclosures for animals that do not require UVB light, but do have live plants growing.

While these fluorescent tubes work well and are reliable, there are some facts and usage requirements that you should be aware of. First of all, any fluorescent tubes will require more expensive fixtures or hood and needs to be no more than 24 inches from the reptile to provide sufficient UVB light. Easch manufacturer is different, so be sure to read the directions provided when purchasing the bulb for more exact placement. Fluorescent bulbs do not provide heat. This can be a benefit or a problem depending on your situation. Since they do not provide heat, they are ideal for reptile and amphibians that come from a more temerate area where overheating is more of a concern than too cool of an enclosre. This also means that for desert and tropical reptiles that you will need to provide other heat sources like incandescent basking bulbs, ceramic emitters, or under the tank heaters to give sufficient heat for your reptiles.

Fluorescent power compact bulbs are almost exactly like their fluorescent tube cousins with the many of the same benefits and disadvantages of fluorescent tubes except they have been engineered to fit in a standard incandescent socket. This means that you can use less expensive incandescent fixtures. The power compacts may be a bit more expensive and may not light the same area as a tube though. Just like fluorescent tubes, power compacts also need to be replaced every six months

The UVB fluorescent bulbs work because of a special coating on the inside of the bulb that cause the UVB wavelength. Unfortunately this coating usually wares out before the bulb burns out. Since we cannot see the UV wavelengths produced by the bulb most manufactures recommend replacing all fluorescent tubes every three to six months, even if they look fine. It's important to keep accurate records of when you've replaced the bulbs so your reptile always receiving a sufficient amount of UVB light. Some tricks that can help is to mark the installation or expiration date of each bulb with a permament marker when installing it or by scheduling a time (like daylight savings time change) to replace all of your fluorescent bulbs.

Mercury vapor bulbs provide many advantages over traditional fluorescent bulbs. Depending on the type of bulb used, the mercury vapor bulbs can be mounted several feet away from the reptile or amphibian and still provide sufficient UVB light. They also use regular incandescent fixtures and most are come with their own ballasts. Mercury vapor bulbs also generate heat, though not as much heat as a similar wattage incandescent bulb. Mercury vapor bulbs also last for a year or more (depending on manufacture) and do not require to be changed as often as fluorescent bulbs.

Mercury vapor bulbs can be more expensive then fluorescent bulbs. However after factoring in costs of fluorescent replacement costs, special fixtures, and additional the energy costs for incandescent heat bulbs, ceramic emitters, or under the tank heaters they will often be less expensive to maintain over the course of a year.

None of the bulbs mentioned here even come close to the amount of UVB light that natural sunlight can provide. Even if you can only have your reptile or amphibian outside for a couple of hours, they will still receive more UVB light then they would of all day under a UVB bulb. Outdoor enclosures are not practical for all types of reptiles and amphibians and there are many parts of world where it is impossible to house reptiles outside all year. In that case, one of the bulbs mentioned above can provide a great option when you have to bring your reptiles inside. A little planning needs to happen when thinking about housing your reptiles outside. Simply placing your aquarium outside won't work since glass filters out UV light. Your aquarium will also act as a green house and you run the risk of reptile overheating. Fine mesh screening can filter half or more of the UV light so when building outdoor enclosures try to use the largest possible mesh that will still allow you to safely keep your reptile in while keeping potential predators out.