Reptile & Amphibian Forums

I was wondering if ALL torts need uvb or basking lights. Is it neccesary? Would it be okay for me to put the enclosure next to a window sill and allow sunlight in and cover half of the tank for shade? I would also be putting a heat pad underneath.

Yes, torts do need UVB rays (to synthesize vitamin D - see below), and the sun is the best source of them. Unfortunately, the glass in your window will filter out all of the UVB, so your enclosure would have to be next to an open window. You either need to get him out in the sunshine or put a UVB emitting light source in his indoor enclosure. Also, do NOT use a heatmat on the bottom of your tort enclosure: tortoises need to get their heat from above (think how it would be in nature), and heat mats - even if they don't feel that hot to the touch - can cause tortoises to heat up inside and their organs can rupture, resulting in death. If you must use a heat mat then put it on the ceiling or the wall of the enclosure.

Here's an excerpt from an article on the tortoise trust website about UV:

"Under natural conditions, in the wild, many reptiles synthesise their own vitamin D3 from the UV component of sunlight. Vitamin D3 is essential for the effective metabolism of dietary calcium in reptiles. Certain wavelengths in the UV spectrum (290 - 320 nm) react with sterols in the skin to produce pre-vitamin D3. This is in turn converted into vitamin D3 itself, using a process which also depends upon heat. . Carnivorous and omnivorous reptiles get a high proportion of their vitamin D3 requirement from their food, however, plants do not contain D3, cholecalciferol, instead they contain D2, ergocalciferol, which is far less efficient in calcium metabolism than D3. Herbivorous reptiles kept indoors are, therefore, far more dependent upon the quantity and quality of artificial lighting than carnivorous specimens.

If inadequate vitamin D3 is available, the animal will rapidly develop the condition known as MBD or Metabolic Bone Disease. In this condition, bone density suffers and various other serious metabolic problems occur. Symptoms include swellings, lethargy, general weakness and tremors. The shell may also become soft and pliable. MBD remains the number one killer of captive lizards, tortoises and turtles (snakes are less affected as being highly carnivorous they easily obtain their D3 requirement via their prey). To prevent MBD, adequate levels of calcium must be present in the diet, and adequate (but not excessive) quantities of D3 must be provided by means of dietary supplementation or by exposure to adequate levels of UVB lighting."

Nina