Step 8: Basking lights
Animals such as some tortoises, iguanas, monitor lizards, bearded dragons and certain snakes benefit from basking lights since it is meant to re-create what the sun does in a tropical or desert-type environment. In nature, the sun comes out and warms up the earth's surface such as a rock or the branch of a tree. The reptile lays on it and absorbs the heat from the earth and the sun.
Basking lights are commonly used in conjunction with daylight bulbs. The daylight bulb is there to provide the overall lighting of the cage while the basking light is used to warm a specific portion of the cage such as a rock or a piece of wood.
Basking lights are also commonly controlled with a rheostat since the intention of a basking bulb is to focus a large portion of heat onto a small surface, thus recreating an area that the animal would use to bask in nature. The rheostat can help to adjust the amount of heat the basking light produces, making it less likely for the animal to get burned.
Buying a basking light with the least amount of wattage that you will need and fine-tuning the temperature with a rheostat will produce the best results.
Since desert animals are attracted to areas with higher temperatures, it is important to prevent the animal from getting burned. If the basking bulb has to be inside a reptile enclosure, make sure that the animal cannot climb onto it or touch it, since basking lights get very hot. If using a reflective dome fixture, consider buying a screen that fits over the open end of the fixture.
If the reptile is nocturnal, then these lights are probably not necessary since the animal will most likely be hiding or resting during the day and not basking. It is still important to recreate the proper light/heat cycle for the animal, since the absence of these is what triggers the animal's nighttime activities.
Because of the special function that basking lights provide, there is no fluorescent equivalent like daylight bulbs have. They simply do not put out enough heat. Energy and cost-conscious reptile owners might want to employ some other heating device instead.