Like most reptiles hailing from tropical climates, bearded dragons require supplemental cage heat to thrive. The diversity among commercial heating products intimidates many new bearded dragon keepers, who wonder whether heating pads, heat lamps or hot rocks are appropriate for their pet. While heating pads and rocks may be useful for some reptiles, you should heat your bearded dragon from above, allowing him to warm himself as he would in the wild.
Various manufacturers produce faux rocks that heat up when plugged into an outlet. These "hot rocks" consist of a metal heating element, encapsulated in plastic or ceramic materials. In theory, a cold reptile can use these rocks to heat up when necessary; however, this is not a good method of providing heat to heliothermic -- sun loving -- reptiles. Sometimes, these devices have a rheostat, allowing you to adjust the temperature of the rock. In addition to rocks, commercial manufacturers produce a variety of cage props that contain internal heating elements. These products have the same shortcomings as hot rocks do for bearded dragons, and are not appropriate for them.
Basic Bearded Biology
Bearded dragons are native to the deserts and semi-arid habitats of central Australia. They thermoregulate by moving into the sun when they need to warm up and moving into the shade when they need to cool off. While they may sit atop a warm rock while basking, any heat gained is incidental -- they have evolved to derive their heat from the sun. When trying to maximize their rate of heating, bearded dragons flatten their bodies in the direction of the sun to collect as much sunlight as possible. Cold bearded dragons are often very dark, which is an adaptation that helps them quickly warm in the sun's rays.
Bearded dragons -- and many other diurnal lizards -- possess a well-developed parietal eye. The parietal eye is not an eye in the traditional sense, and does not see images as typical eyes do. While scientists debate the exact functions of the organ, it is clear that the organ plays a role in detecting sunlight. Additionally, some lizards appear to use their parietal eyes to perceive incredibly subtle shadows, which likely help them to avoid capture by predators such as hawks. It is likely that the lizards use these sunlight-detecting organs to assist in thermoregulation; providing them with belly heat may impair their ability to properly heat and cool themselves.
Heat bearded dragons from above using reflector domes and incandescent bulbs. Place the lights at one end of the cage to provide a thermal gradient; this allows your bearded dragon to find a comfortable temperature at all times. The surface temperatures under the basking spot should be about 100 to 105 degrees Fahrenheit. As incandescent bulbs do not emit UVB, you must also use fluorescent light bulbs to provide the light necessary for their health. Radiant heat panels are similar to heating pads, only you suspend them above, rather than below, your pet. If used in conjunction with proper fluorescent lighting, radiant heat panels provide an appropriate solution. Be sure to turn off all lights at night, and maintain a steady diurnal cycle of approximately 12 hours.
- The Anatomical Record: Parietal Eye-Pineal Morphology in Lizards and Its Physiological Implications
- Journal of Experimental Biology: Lizards Respond to an Extremely Low-Frequency Electromagnetic Field
- Melissa Kaplan's Herp Care Collection: The Parietal "Eye"
- Dachiu Bearded Dragons: Frequently Asked Questions
- Animal Diversity Web: Pogona Vitticeps
- Melissa Kaplan's Herp Care Collection: Hot Rocks and Reptiles
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