Why do I need an Expensive UVB Bulb?
By: Timothy Zedi
What is UVB?
Ultraviolet Light is a spectrum of light shorter than visible light. UVA light is visible to some reptiles and insects but not to humans. UVB light induces the production of vitamin D3 which is needed by many reptiles to metabolise calcium. UVC is the strongest wavelength of Ultraviolet light and causes harmful effects in humans and other animals. UVC lamps are used to sterilise surgical instruments as it kills micro-organisms. The most important type of ultraviolet light in reptile keeping is UVB, this is what this article will discuss.
UVB Light and Calcium Metabolism
Diurnal lizards, tortoises, terrapins, turtles and crocodilians require access to UVB light in order to produce vitamin D3. In their natural habitats these reptiles spend large amounts of time basking in the sun and perform their daily activities on sunny days. The UVB light in the rays of sunlight are absorbed by special cells in the reptile’s skin and vitamin D3 is produced. Vitamin D3 is used by the reptile to metabolise calcium. The way a reptile metabolises calcium is a complex process which involves not only skin cells but also the circulatory system and several internal organs including the kidneys and parathyroid gland. Calcium is needed for bone growth, bone regeneration, egg shell production and nervous system health. Too little calcium will lead to Secondary Nutritional Hyperparathyroidism formally called Metabolic Bone Disease. Secondary Nutritional Hyperparathyroidism is a horrible disease that causes bone deformities and eventually death. The best way to avoid this problem is to provide a good quality UVB light and a diet high in calcium. Calcium and vitamin D3 supplements alone do not stop this illness, a source of UVB is required. To make things simple your Bearded Dragon, Iguana, Monitor Lizard or Terrapin cannot metabolise calcium without a source of UVB light. UVB light can be provided by access to natural sunlight or by special light bulbs. Note that glass or plexi glass filters out UVB light. Placing your reptile cage next to a window in a sunny room will not provide it with UVB.
Evolution of UVB Lamps
Before the advent of special UVB lamps it was near impossible to keep most reptiles excluding nocturnal geckos and snakes. Wild caught Tokay Geckos where the most popular lizard in the pet trade for many years because these lizards are nocturnal and therefore don’t require UVB light. The use of black lights (these are used in checking bank notes and give of weak UVB light) is mentioned in the older books on lizard keeping. Zoo Med developed the first UVB lamps for use in reptile cages in 1993. Since then many other companies manufacture UVB lamps for reptiles. UVB lamps have different UVB strengths for different habitat types. Lower strengths are used for forest dwellers and higher strengths are used for desert dwellers. Modern reptile specific UVB lights have made the keeping and breeding of sun loving reptiles common place in the 21st century pet trade. UVB lamps come in linear fluorescent tubes or compact fluorescents lamps that resemble the energy saving light bulbs found in most South African homes. Linear tubes will need to be fixed to the side or top of the cage and require a special ballast in order to operate. Compact UVB lamps fit into the same screw fittings used for heat lamps. Mercury Vapour Bulbs which give off UVB light as well as heat are now available. I would avoid mercury vapour bulbs as they are expensive and cannot be used during summer in South Africa as they will overheat the cage.
If you can’t afford A UVB Lamp Don’t Buy the Lizard
I have witnessed far too many people come up to my stand at reptile expos with a baby Bearded Dragon or Green Iguana in a tub and walk away with basking lamps but no UVB lights, even after telling the owner the importance of having a UVB lamp. In simple terms your Bearded Dragon, Iguana or Chameleon will die without a UVB lamp in its cage. If you cannot afford the cost of a UVB lamp which needs to be replaced yearly, rather buy a reptile that does not require a UVB lamp such as a Leopard Gecko or Corn Snake. I often put the reluctance to buy a UVB lamp to the fact that the prices for some lizards have dropped dramatically and in many cases a UVB lamp will cost more than the actual lizard. Back in the days when a Bearded Dragon cost R1000 or more you made sure you purchased a good quality UVB lamp to keep your rare and expensive pet reptile alive. Today Bearded Dragons are anything but rare and expensive, with hatchling bearded dragons available at every pet shop in the country, costing around R100.The mom or dad who buys these pet dragons for their children must realise that the dragon still needs a UVB lamp no matter if the UVB lamp costs more than the lizard. If your Bearded Dragon lives for ten years and you replace your UVB lamp each year at a cost of R300 per bulb you will need to spend an average R3000 on UVB lamps to keep the dragon healthy for those ten years. Iguanas can live twice as long as a Bearded Dragon so the cost of UVB lamps is even higher for this lizard. Lizards kept in outdoor enclosures that have access to natural sunlight do not need a UVB Lamp. The lizard will require at least 2 hours of natural sunlight each day to fulfil its UVB requirements.
What Happens to a Lizard Kept Without a UVB LAMP?
A new pet Bearded Dragon, Green Iguana or other lizard is put in a cage without a UVB lamp as the new owner sees a UVB lamp as an unnecessary expense. The lizard seems healthy on the outside but what’s happening on the inside? A lizard needs calcium for bone growth especially when growing up. A fast growing lizard such as a Bearded Dragon needs calcium to form new bone as it gets bigger. As the lizard does not have access to UVB it cannot metabolise the calcium it needs to develop bone. As this lizard grows its bones will be softer than usual and its bones will not form properly leading to deformed jaw bones, limbs and spine. This takes a long time and the bones can be so deformed that the lizard has to be euthanized. Iguanas get “Rubber Jaw” where the jaw bone resembles cartilage rather than hard bone, this is caused by a lack of UVB. A Chameleons tongue is shot out using a bone on the inside of the lower jaw. If you keep a chameleon without a UVB lamp this bone can be effected preventing the chameleon’s tongue from working properly. Chameleons with this problem will refuse to feed on their own requiring a life time of hand feeding. A lizard’s body needs calcium for other functions such as coating nerves and for producing egg shells. If no UVB is available, the lizard’s body will remove calcium from its bones for these functions. An X-ray of a lizard with calcium deficiencies will show faint ghost like images of bones rather than bold white images. Climbing lizards such as Green Iguanas can break limbs for this reason as bones are brittle. Calcium deficiencies will lead to egg binding in lizards. Egg binding can be fatal and often requires surgery. Prevention of these problems is as simple as providing a UVB lamp.