Reptile UVB Lights Explained

The Importance of UVB to Reptiles  

UVB and warm body temperatures tag-team to help reptiles turn cholesterol into vitamin D3. This vitamin helps support immunity, digestion, kidney functions, growth and reproduction. Vitamin D3 is especially important for healthy bones and muscles because it helps reptiles absorb the calcium from their food. 
Not getting enough UVB, a lack of warmth and poor nutrition can lead to all kinds of health problems, the most common being metabolic bone disease (MBD). In addition to broken bones, MBD can cause weakness, tremors, seizures and reproductive problems. Vitamin supplements can help prevent MBD and other medical conditions; however, having a UVB light in your pet’s enclosure is still the best way to go.   

Different UVB for Different Reptiles

You may have noticed UVB lights are labeled with numbers like 5.0 or 5%. That number refers to the total UVB output of that bulb. For example, if it’s a 5.0 UVB light, that means 5% of the light emitted from the bulb is UVB and 95% ultraviolet A (UVA) and visible light. 

Generally speaking, 6.5 to 7.5 is considered a medium amount of UVB. Anything 10 or above is considered high. You should also become familiar with Ferguson Zones. These categorize reptiles into four groups based on the ultraviolet light index that they would be exposed to out in the wild. 

• Ferguson Zone 1: Crepuscular/Shade Dwellers
  Low UVB requirements. These reptiles are usually out and about during twilight hours. Includes leopard gecko, crested gecko, corn snake, Burmese python and milk snake.

• Ferguson Zone 2: Partial Sun/Occasional Baskers
  Moderate UVB requirements. These reptiles go out in the sun for short periods of time. Includes ball python, ornate box turtle, green anole and Australian water dragon.

• Ferguson Zone 3: Open/Partial Sun Baskers
  Medium-high UVB requirements. These reptiles spend a lot of time basking out in the sun. Includes bearded dragon, Yemen chameleon, leopard tortoise and frilled lizard. 

• Ferguson Zone 4: Mid-Day Sun Baskers
  Very high UVB requirements. These reptiles bask in the sun when UVB levels are the highest (i.e., mid-day). Includes chuckwalla, Texas horned lizard, uromastyx and rhinoceros iguana. 

Pay close attention to any lamp-to-animal distance information the manufacturer provides on their packaging or website. The combination of UVB number, distance and Ferguson Zone number will light the way to the right bulb. A higher numbered light can provide the right amount of UVB at a further distance. Yet at the same time, that same light at a closer distance could be too much UVB. You should also replace a UVB light about every 6 months because the special glass used for the bulbs become less transparent over time.  

The Difference Between UVB, UVA & Basking Lights

Reptiles cannot see UVB. On the other hand (or claw), UVA can be seen by reptiles and influences activities such as eating, movement and mating. All UVB lights emit both UVA and UVB rays. Not all UVA lights give off UVB rays, so it’s important to have a UVB light for your reptile. Your pet’s enclosure should also have a basking light. 

Reptiles are cold blooded and rely on external heat sources to warm their bodies. Basking lights (also available at Pet Supplies Plus) emit heat that help reptiles regulate their body temperatures; however, they do not produce UVB. For that reason, your UVB and basking lights need to be positioned in such a way that they become one beam of light. This recreates the sunlight your reptile would normally bask under in their natural environment.   

Conclusion

A reptile must have access to UVB to produce vitamin D3: a key nutrient that supports several important bodily functions. For your terrarium, choose a UVB bulb based on UVB number, the distance it will be from your pet and what Ferguson Zone the reptile belongs to. If you have more questions, stop by your local Pet Supplies Plus store. We can help shed light on all kinds of reptile care topics, including UVB.