8. Temperature/Thermal Gradients
Like all reptiles, chondros thermoregulate by locating a comfortable temperature within their environment. Therefore, it is necessary to establish a temperature gradient (from cool to warm) to enable thermoregulation. A typical gradient is in the range from 75˚ to 88˚ F. Actual measured temperatures can depend on factors like vent placement, the source and wattage of heat provided, and the ambient room temperature. If ambient room temp is too high (close to the temp of your cage) it will be more challenging to achieve a broad thermal gradient. Also, fluorescent lights emit heat and may interfere with the temps you are targeting. In this case you might need to use different lighting, or experiment with light location.
To achieve a thermal gradient, heat sources are always offset to one side of an enclosure. In the case of top heat, the RHP, ceramic bulb, etc. is situated to the left or right side. When belly heat is used in a rack, heat tape is commonly situated to the rear of the tub. Therefore with belly heat and back heat a natural gradient is created from front to back.
When establishing your thermal gradient it is important to read what your chondro is telling you. If it constantly perches in the hot spot, your maximum temp may be set too low. If it habitually perches as far from the heat source as possible, or routinely grounds itself, your maximum temps may be set too high. An infrared temperature gun is a valuable tool and is highly recommended for setting up your thermal gradient. It will provide quick feedback about the surface temps of your chondro, perches, the ground, etc. and will enable you to dial in your temps with greater confidence.
It should be noted that sometimes a GTP will perch in a suboptimal location at the expense of receiving adequate heat. An example is when a newly acquired chondro is grounded for several days. In this case the animal is likely selecting a location that provides more security at the expense of getting enough heat. If this is observed for multiple days it will be necessary to make adjustments to encourage perching. If not, sustained stress-related grounding may lead to health issues. This will be covered in more detail later.