Do I Need UVB Lighting for My Tortoise or Turtle?
This is the most commonly forgotten part of the tortoise habitat. Many people opt not to buy the most expensive piece of a set up when they get their tortoise from a pet store.
These same people also tend to depend on the pet store associate to help them buy what they need for their new tortoise and unfortunately they are often told that UVB lighting is not necessary.
UVB lighting may not seem like a big deal but it is. Without UVB lighting your tortoise can and will develop metabolic bone disease, be unable to synthesize Vitamin D (which causes calcium metabolism problems), and even be lethargic and have a lack of appetite. UVB lighting is very important.
Providing UVB Lighting
Natural sunlight emits invisible UVB rays in the wild. Artificial UVB rays are delivered to your pet tortoise in an indoor enclosure through special reptile bulbs that need to be changed every 6 months, even if they haven't burned out. The rays will run out and at that point will be nothing but visible white light and of no purpose to your tortoise.
UVB rays must also be able to reach your tortoise without being scattered or blocked by glass, plexiglass, or screens.
An ideal distance between your tortoise and his UVB light is 10-12 inches with nothing in between him and the light. A mesh screen is O.K. to set your UVB light on but it does decrease the amount of invisible rays that will penetrate through to your tortoise. Therefore I recommend mounting the fixture on the inside of the enclosure when possible while still keeping it 10-12 inches from your pet.
A light that is too close will cause thermal burns on your tortoise, much like a tanning bed would, and a light that is too far away won't do much good at all because there won't be enough UVB rays that reach your pet.
UVB Light Options
The most traditional type of UVB light is the fluorescent strip light. This bulb looks like any other fluorescent bulb that you'd find on the ceilings of most any school or place of business but it is really a special reptile bulb. Regular fluorescent lights do not emit UVB rays.
More recently other UVB light bulbs have come on the market. The compact fluorescent UVB bulb looks like a corkscrew or has a few small fluorescent tubes that create the bulb and is good if you don't have the right fixture for a fluorescent strip light but you do have an extra clamp light laying around. The downside to these bulbs is that it only covers a small area, unlike an 18-inch or 36-inch long strip light.
Mercury vapor bulbs are more expensive but typically last longer, are much more powerful than other UVB bulbs, and also emit heat.
These are great for large enclosures or entire rooms that house larger tortoises.
Providing Heat Lights
Many tortoises require basking temperatures in the 80's and 90's so supplemental heat is needed. Heat lights are preferred over under tank heaters because you can control the ambient air temperature. Undertank heaters often have little or no settings to control the heat and primarily warm the bottom of the enclosure while failing to warm the ambient air temperature.
There are a variety of heat lights for tortoises but it is important to find out what wattage you need to keep the tank at the desired temperature for your specific tortoise while creating an appropriate thermal gradient. Larger enclosures will need higher wattage bulbs and smaller enclosures will naturally need a lower wattage.
There are ceramic heat emitters which only give off heat, no light, and screw into a clamp light. These are great because they last a long time, are less fragile than the light bulbs, and can be used day or night since they don't give off any light. White heat light bulbs should only be used during the day so you don't stress your tortoise but you can switch over to a red or blue/purple heat light at night.
For temperature details, refer to the care sheet on your specific tortoise.
With proper UVB exposure and appropriate heat lights, you can avoid many of the common problems tortoise and turtle owners face.