Your pet herp, being cold-blooded, relies on you to provide an environment that allows him to stay healthy.
Environmental temperature is critical to herps. Most snakes, for example, will not eat if their instincts tell them to hibernate. Most may need temperatures between 80° and 88ºF, but depending on the animal, the optimal range may well lie within only two to four degrees. A temperature gradient should be provided in the habitat to allow your herp to move from place to place, to warm up by basking or to cool down, as desired. Also, in the wild, some herptiles are accustomed to having the temperature drop from 5 to 20 degrees at night. Some reptiles, when kept at a constant temperature, may eventually develop heat stress and die. For many species, a time-controlled programmable thermostat that changes from day to night will help to ensure that your pet stays healthy. Depending on the animal that you select, you will need to purchase and maintain the proper equipment to adequately control the temperature.
Lighting needs, like temperature requirements, have been programmed into herps through evolutionary millennia. Light not only provides your pet with Vitamin D for mineral metabolism, but it also creates an environment that caters to the animal's very nature.
While most tropical species need constant, near 12-hour cycles of day and night, reptile species from more temperate regions are accustomed to fluctuation in the day/night cycle, ranging from 16 hours of darkness in winter to 8 hours in summer.
For many herps, a light source can be used both for light and heating. For most herps, an ideal light is a full spectrum fluorescent bulb or a UVB reptile light can be fitted to the top of the vivarium, or onto an overhead fixture. This will provide the necessary wavelengths of light your herp needs for the synthesis of Vitamin D. An incandescent bulb can be added for light and heat.
Species that require darkness with higher ambient temperatures should have a heating source to use at night such as an under-tank heater like the Repti Therm Under Tank Heater or nocturnal heat lamps. Careful monitoring with a thermometer is critical.