A reptile thermostat is a device that you use with a heating device for a reptile vivarium. It controls when the heating device comes on and off by altering the electric signal that it receives. Thermostats have a sensor that is placed in the vivarium. You set a required temperature on the thermostat. Once the sensor detects that the specified temperature has been achieved, the thermostat turns off the heater or decreases its power. When the temperature drops again, the thermostat turns the heater back on or increases its power.\r