Husbandry (Caging) for Terrestrial and Arboreal Reptiles
Dr. Nancy Anderson
Controlling humidity in caging for tropical animals can be challenging. Most houses have relatively low environmental humidity, therefore the easiest method of producing high humidity in a cage is to completely enclose it. This however does not allow for adequate air circulation. Many people use automated cool air humidifiers or rain generators and fan systems to provide adequate humidity to tropical species. Some people are successful misting cages throughout the day (time consuming) or bubbling air through a container of water. In areas where the climate is warm and humid, placing cages in outdoor areas or on screened porches can be the best solution.
Aside from tropical species, the environmental humidity should be kept low for most species. High humidity predisposes build-up of infectious agents and wastes such as ammonia. Excellent sanitation allows removal of wastes and adequate ventilation allows evaporation of residual moisture.
Ventilation holes or screening on top of the cage is usually adequate for non-aquatic species. Screening does not work well for animals that pace their cages because it causes severe abrasions. In this case, it is better to use pegboard or drill other ventilation holes.
In addition, reptiles should not normally pace a cage. This is a sign that the husbandry is not adequate. Check the cage regularly for temperature range, adequate hiding places and other environmental necessities. Even when the cage humidity is low, a "moist" refuge should be available. This usually consists of damp clean sand (desert species) or sphagnum moss placed in a plastic hide area. If the reptile needs increased moisture, it can select to spend a few hours in the hide box.
Make sure to read about the natural history of your pet species. Depending on their lifestyle and native range, they will have very different temperature requirements. Do not assume that your pet has average requirements. Check it out. Buy at least one accurate thermometer. Your hand cannot tell you if a cage is warm enough, because it measures temperature relative to the temperature in the room. Therefore, if a cage temperature is 75 degrees Fahrenheit and it is wintertime, it will likely feel warm to you. But if it is summertime, it might feel cool. Use a thermometer.
Maintain the cage air temperature as a gradient (gradual temperature range) incorporating as much (at least 80 percent) of the temperature range that the animal experiences in the wild as possible. One of the easiest ways to accomplish this is to place a heat source at one end of the cage. Commonly used heat sources include undercage heating pads (best for burrowing animals) and heat lamps. "Hot rocks" are usually not good choices because they are prone to hot spots and can cause severe thermal burns on your reptile. In addition, most reptiles gain heat while basking, so the heat comes from their backs. The blood vessels in their bodies are positioned to shunt heat from their backs to the rest of their bodies, so heating the abdomen by lying on a "hot rock" is not as effective.
Heating pads or thermal tape is best used for reptiles that usually don't bask but get their heat from sitting under rocks or in soil that was heated by the sun. Heating pads are safest when they are placed under 1/3 to 1/2 of the floor of the cage. The cage floor should be glass or plastic so that it transmits an even level of heat. Place the cage on blocks that leaves a 1/4" air space between the pad and the floor of the cage. This air space will prevent hot spots. With undercage heating, it is important to move a thermometer around in the substrate to measure the temperatures anywhere that the reptile might be able to burrow. It is just as important to make sure that the soil gets hot enough as to make sure that it is not too hot. In addition, to avoid overheating accidents, control the heat source with an accurate thermostat.
Heat lamps are the best methods of providing heat for basking reptiles; however, heat lamps can produce extremely high surface temperatures and care is needed to avoid thermal burns and fires. The best type of heat lamps are ceramic (produce no light) or infrared (produce only red light). These lamps are better because they do not produce light in the visual range so they can be left turned on at night. Regular light bulbs can also be used to provide heat, but if left on 24 hours a day many reptiles will stop eating because they never experience a night, rest period. Regular light bulbs are a reasonable choice for desert species that experience very hot temperatures in the day and then very cool temperatures at night (the lights can be turned off).
Thermal burns are a common occurrence in pet reptiles. To decrease the likelihood of thermal burns if a heater malfunctions, be certain that the surface temperature at the hottest spot is less than 105 F. Check the temperature of any surface with a thermometer. In addition, place a hand under the heat lamp at the closest basking site for 15 minutes after the basking lamp has been on for 2 to 3 hours. If it is uncomfortable to leave your hand (this is not a temperature response but a pain response, so your hand is very accurate) in one spot, the lamp is too intense. Either move the lamp further away or use a rheostat to decrease the intensity. This also reduces the possibility of a fire.
ANY heating elements that can attain temperatures over 105 F can produce life threatening thermal burns. The elements must be shielded from the direct contact by the reptile. Ideally, place heating elements outside of enclosures. Heat lamps work best if they shine through wire mesh and the reptile cannot directly contact the mesh. Be careful when shining into enclosures with poor ventilation (small aquariums etc.), temperatures can rise rapidly (greenhouse effect). This is also the reason why it is not smart to place a reptile in a glass or plastic aquarium outside in direct sunlight.