Cold-blooded animals such as reptiles and amphibians that are kept at home in a terrarium rely on external sources for body temperature regulation. This is called thermoregulation. There are different ways to safely heat a terrarium. The various methods can be used alone or in combination with other methods of warming a terrarium environment.
Common heating method for terrarium is by using heat rocks. However, heat rocks should not be used as the primary source of heating for your reptile vivarium. Heat rocks are simply heating pads in the shape of rocks that duplicate the heat that a lizard would obtain from a sun-warmed rock. For most reptiles that need belly heat, the rock will feel almost neutral or barely warm to the human touch. The rule of thumb with hot rocks is that, the temperature of the rock must be in the same range with human body temperature. If the rock should feel warm or hot for you to touch, it is dangerously warm for the reptile.
Ideal heat rocks are those that does not exceed 100 degrees Fahrenheit, or purchase one with temperature controls for easy adjustment. It should also be waterproof and can tolerate the humid conditions of a tropical environment. Some heat rocks emit heat unevenly, causing serious burns to lizards.
Monitor the temperature of your terrarium. Install a special thermometer inside the terrarium to monitor the temperature of the terrarium. If not regulated properly, reptiles cannot accurately sense the temperature on their belly and can get severe burns from a rock that’s too warm