By: Dr. Nancy Anderson
A great deal of thought must go into a reptile's captive environment. You must consider the size and shape of the enclosure as well as the materials from which the enclosure will be constructed.
Cages need to be escape proof, non-abrasive and easy to disinfect. They should also be well insulated and roomy. Aquariums, plastic sweater boxes and plastic tubs can work well for small reptiles. Larger species such as adult green iguanas, large boas or pythons, and large tortoises usually require custom made cages ranging from closet size to room size.
Custom cages can be home made using polyurethane sealed wood and glass/plexiglas. Non-sealed wood is not recommended for caging because it is impossible to disinfect and will harbor bacteria, odor and parasites. Before being used, cages should be aired out for at least one week to remove polyurethane fumes. Some companies specialize in building custom pet reptile cages in people’s homes. Many of these companies use fiberglass enclosures and can make the enclosure as complex as you wish by controlling lighting intensity, humidity, temperature cycle and even rainfall.
Cage wall surfaces should be smooth to prevent damage to your reptile’s nose and skin. You can add a rough branch or stone to the enclosure to aid in shedding. All reptiles need places to hide, and having a “safe zone” reduces stress and prevents cage pacing. Provide enough hiding places so that each animal has his own place to hide.
Cage furniture should be constructed of non-porous material like plastic, metal, glazed ceramic or polyurethane sealed wood, so it can be disinfected. Or it can be disposable, such as clay flower pots, branches and rocks. You can choose from the many commercial products available. Plastic ice cream containers with holes cut in the side, plastic pots and plastic plants also work well. For animals requiring higher humidity, containers can be filled with damp, clean sphagnum moss. The moss should be changed approximately every 2 to 3 weeks to prevent buildup of bacteria and wastes.
The cage should also include structures to stimulate physical activity. These should be sturdy so that your reptile cannot fall. It is easiest to clean the cage if these structures are removable. Large structures also provide visual security so that cage mates can hide from each other if necessary.
Furniture for Arboreal Reptiles
The cage space for arboreal reptiles needs to be vertically oriented, which means higher than it is wide. It should include objects for climbing, but do not place these structures over food or water bowls to prevent contamination with feces or food. It is best to mount food and water dishes in the climbing structure. In general, willow, birch, beech, ficus and fruit trees provide non-toxic branches.
Reptiles require adequate space to be healthy. The following are minimum size recommendations, but the general rule is the more space the better. Snakes need room to stretch out at least two thirds their entire body length. Tortoises require at least three times their body area. Supply at least 6 square inches of cage space per inch body length in lizards. Double or triple space requirements when adding additional cage mates.
Plenty of space and visual security is essential when housing more than one animal in an enclosure. Signs of inadequate cage space are cage mate aggression, disease, high parasite loads, starvation, dehydration and cannibalism. Some animals naturally prey on cage mates, so these animals should be housed alone.
Do not mix species. Doing so is often disastrous because organisms that do not cause overt disease in one group of animals may be deadly for another. For example, amoebiasis doesn’t usually cause significant disease in turtles, but often kills snakes.
Quarantine all new animals for at least 90 days. Ideally, they should be quarantined in a separate building, but if this is not possible, quarantine animals in separate rooms. In addition, take these precautions:
*Make sure that the air supply from the quarantine room does not enter rooms where the rest of the reptiles are housed.
*Feed and clean new animals last and make sure that clothes do not become contaminated. You may wish to have a separate pair of shoes and a smock to use in the quarantine room.
*Dispose of wastes and wash hands thoroughly.
*Clean and disinfect food and water dishes in a separate area.
*Have new reptiles tested for parasites and infectious disease by a reptile veterinarian before placing them in the main collection.
Reptiles rarely come in contact with their feces or spoiled food in the wild. In captivity, the goal is to minimize this contact and the chance of spreading disease when it occurs. The most important part of cleaning is removal of fecal material, urates and left over food. This can be as simple as removing a piece of newspaper or as time consuming as scrubbing stones. Only after the gross debris is removed can disinfectants destroy microbes that cannot be killed with soap and water alone. Disinfection is not a substitute for cleaning. The best cleaning solution is dish soap and water.
Diluted bleach (1 part bleach to 15 parts water) is an inexpensive, safe and effective disinfectant for use around reptiles. It works best if allowed to remain on the surface for 15 minutes before being rinsed. Thorough air drying the disinfected items decreases the likelihood of microbes survival. Bleach does not work in organic debris, so it is important to clean with soap and water first. Chlorhexidine and Roccal® are disinfectants that are safe to use with reptiles. Phenolic cleaners such as Pine-Sol® and Lysol® can be toxic to reptiles and should be avoided.
Non-sealed and porous surfaces cannot be disinfected thoroughly. Therefore, if a disease outbreak occurs, discard items such as wood, pottery, artificial turf and bedding. Never transfer these items from one group of animals to another.
Substrates and Light Cycles
Newspaper (black and white print) and butcher paper are ideal cage liners. They are non-toxic, inexpensive and disposable, and they have the considerable advantage of completely removing wastes from the cage. They also allow owners to see the amount and condition of feces and to estimate amounts of leftover food. Papers should be changed after defecation or soiling with food.
Artificial turf is a good alternative to newspaper and many people consider it to be more aesthetically pleasing. Change the turf as soon as it is soiled. Astroturf is best cleaned by washing it in dish soap and water, rinsing, soaking for 15 minutes in a one part bleach: 15 parts water solution, rinsing and then air drying. If possible, dry the turf in direct sunlight, as the ultraviolet rays from the sun have a natural antibacterial effect. In general, it requires two days to clean and dry turf completely, so you will need two to four “sets” of turf for your reptile cage, depending on the frequency of soiling. Be sure to trim off loose strings to prevent pet reptiles from mistakenly eating them.
Rabbit or guinea pig pellets and recycled paper bedding (made for pet reptiles) may be used for cage bedding for herbivorous reptiles if they are replaced frequently. If the bedding is mistakenly eaten, the pellets and paper will pass through the intestines without causing an obstruction. In fact, the pellet will provide additional nutritional value. These substrates work best for desert animals that produce smaller, dry feces. When these substrates become wet, they mold very quickly, often in less than 12 hours. Even with dry conditions, the pellets will eventually mold, so it is wise to change them completely at least every two weeks.
Large stone gravel and bark chips can also be used, but are less desirable because they can be eaten and will harbor bacteria, parasites, moisture and odor. They are more expensive to replace frequently. Large gravel can be washed, bleached, rinsed and sun dried, but this requires a lot of work. Food debris and feces need to be removed on a daily basis and the substrates need to be changed when soiled, about once a month.
Sand is recommended for desert species only. Non-desert species often become impacted with sand and defecate too frequently to keep the sand clean and dry. Also, when kept clean, sand provides a low humidity environment which is not suitable for animals from more moderate climates. Sand should be maintained similarly to large gravel.
Do not use kitty litter, corncobs or small gravel as cage substrate. These materials are often ingested causing intestinal impactions and are frequently associated with skin infections. Some people keep snakes on wood chips successfully, while others have experienced problems with their snakes becoming impacted. Avoid using wood chips that have high resins contents such as cedar and certain pines. Black walnut is also not recommended.
Provide 10 to 14 hours of light and dark daily. Base the proportion of light to dark on seasonal variation in the animal’s home range. Room light or regular light bulbs left on to heat cages overnight does not provide adequate darkness. If lights must be left on in a room during the night, completely cover the cage. Lack of a normal light cycle predisposes reptiles to disease.
Most herbivorous and insectivorous reptiles require ultraviolet light of a very specific wave length range (280 to 315 nm). The needed range and intensity is best provided by exposure to unfiltered sunlight, not passing through glass or plastic. Ideally, pet reptiles should be exposed to direct sunlight for one to two hours two to four times per week. If climatic conditions make this impossible, artificial lighting will be required.
Lights used for growing plants do NOT produce the correct wavelengths used by reptiles. You will need to purchase special lights made just for pet reptiles, which you can find at better pet stores. Although these bulbs will produce light that you can see for months, they only produce the correct wavelengths for approximately 4 months and need to be changes three times per year.
The intensity of these lights is much less than the sun, so reptiles need to be exposed for several hours each day. The strength of the light falls off extremely rapidly as the distance from the light increases, so basking sites should be located within 18 to 24 inches of the light. Contact with the light should be prevented. The longer the light fixture, the better the intensity, so one longer bulb is better than two shorter bulbs. Buy the longest light fixture that you can. Be sure to turn the ultraviolet light off at night.
Humidity and Temperature
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.