Management and Husbandry of Reptiles
Veterinarians must not only be familiar with common reptile species and their management but also be able to extract clinically relevant husbandry information from the owner in a timely manner. The use of a history formcan greatly facilitate this process and ensure that nothing is overlooked.
Different species from different locations must not be mixed. Ideally, only a single species should be kept in any enclosure, and care must be exercised to avoid competition for resources such as food, basking areas, and retreats. In general, the solitary reptile pet is often the healthiest. Most nonbreeding pet snakes and aquatic turtles are best maintained as a single pet, because trauma while feeding is common in groups. Some lizards, notably the chameleons (Chameleo spp), are so territorial that isolation is often essential for longterm survival of the captive pet.
The size of the enclosure is important, and although many breeders and retailers may be able to intensively manage stock, pet owners should be advised on minimum enclosure sizes (see Table: Recommended Minimum Space Requirements for Reptiles), the importance of providing the largest enclosure possible, and correct cage furniture. The type of enclosure (arboreal, terrestrial, subterranean, or aquatic) should be appropriate for the species (see Table: Important Husbandry Requirements for Selected Reptiles). In certain areas, the climate may permit keeping reptiles in outdoor enclosures, which is highly desirable, although theft, escapes, predators, and wildlife carriers of disease should be considered. Just 1–2 hours per week of unfiltered natural sunlight can have dramatic, positive effects on health, so owners should be encouraged to provide natural sunlight whenever conditions permit.
Glass aquaria are commonly used, but the greater visualization perceived as an advantage to the owner may be stressful to the reptile. Glass is also a poor insulator, and greater heat loss may lead to dramatic temperature fluctuations. Even if the entire top of the enclosure is covered by mesh, ventilation may be severely hampered. Wood, plastic, or fiberglass enclosures are more expensive, more versatile, and preferred. Typically, significant investment is required for an appropriate enclosure, which must be considered as part of the overall pet budget.
Newspaper, artificial turf, and organic particulates (eg, bark chips) are suitable materials to line cages and vivaria, but they must be completely replaced regularly. Soil, sand, and natural leaf litter can also be used, but oven baking is recommended to sterilize before use. Gravel and pebbles are not recommended for terrestrial species, because they are difficult to clean and often ingested. Other essential items include a water bowl (large enough for the reptile to bathe) and various retreats (eg, cardboard boxes, cork bark, shredded paper). Clean, secure branches are required for arboreal species. Soap and water is generally all that is required to clean cages, but bleach can be used as long as rinsing is thorough. Some cleansers (eg, phenolic disinfectants) are toxic.
Recommended Minimum Space Requirements for Reptiles
Important Husbandry Requirements for Selected Reptiles
A variety of heaters can be used, including incandescent bulbs, infrared ceramics, heating pads or mats, warming cables, tubular heaters, radiators, convector heaters, and natural sunlight radiation. Heaters of an appropriate size should be thermostat controlled, screened from the animals, and positioned toward one end of the enclosure to provide a thermal gradient. “Hot rocks” frequently result in burns in larger animals and should be avoided. Light bulbs cannot be used to provide nocturnal heat, but some mercury-halide bulbs can provide heat and broad-spectrum lighting.
All reptiles benefit from broad-spectrum lighting. However, UVB light (290–300 nm) is especially important for most diurnal lizards and chelonians for vitamin D3 synthesis and calcium regulation. The best source of lighting is unfiltered sunlight. However, many artificial fluorescent strip-lights, compact fluorescent, and mercury halide bulbs are available. The quality and intensity of these artificial lights should always be considered second best to sunlight but can be instrumental in preventing disease. Almost every light marketed for reptiles has the term “broad" or "full" or "natural” on its packaging, creating confusion for veterinarians and owners alike. Appropriate lights must be labeled as providing UVB or, better still, be examined and tested using a spectrometer. Even suitable fluorescent lights must be placed relatively close to the reptile (<30 cm), and replaced every 9–12 months. Mercury bulbs can provide greater penetration, up to 1 m or more, and can be replaced every 12 months. Most transparent plastic and glass barriers filter out UVB wavelengths. A photoperiod of 12 hours/day is suitable for general maintenance.
Humidity that is too high or low can create serious problems. Humidity is seldom directly controlled, although the advent of dedicated humidifiers and sprinkler systems makes this practical. Decreasing ventilation to maintain temperature and humidity is ill advised and frequently causes skin and respiratory disease.
Although the incubation period of many reptile disorders is unknown, quarantine periods of 3–6 mo are recommended. Owners should also be encouraged to keep detailed records of any changes in husbandry or nutrition, breeding activity, in-contact animals, disease outbreaks, health issues, recent additions, and previous problems and treatments.
Species identification is essential to critically appraise captive diets (see Table: Composition of Animal Foods that May Be Offered to Reptiles and see Table: Composition of Plant Foods that May Be Offered to Reptiles). Rodent-eating carnivores such as most snakes present few problems as long as the rodent is recognizable to the snake as food. Obese rodents that have been frozen for prolonged periods may contain fewer nutrients and provide excess calories. Feeding live rodents is not advised (and is illegal in many countries) because of the dangers of prey-induced trauma to sedate reptiles and the welfare implications for the live prey. Insectivorous reptiles can be well catered for with a variety of commercially available crickets, waxworms, tebos, hornworms, locusts, mealworms, cockroaches, earthworms, flies or fly larvae, and aquatic invertebrates. Feeding insects a nutritional diet high in calcium and dusting the insects with a high-calcium reptile supplement (eg, calcium carbonate) immediately before feeding is required to prevent deficiencies.
Composition of Animal Foods that May Be Offered to Reptiles
Providing herbivorous reptiles with a varied and nutritious diet can be difficult. Foods with a high calcium:phosphorus ratio should be selected with due regard given to the species-specific requirements for vegetables and fruits. Human nutrient databases can be useful (http://ndb.nal.usda.gov/). Calcium or vitamin D3 deficiency (generally due to poor quality lighting and low-calcium diets) leads to secondary nutritional hyperparathyroidism in insectivores and herbivores. A variety of commercially available foods are available in moist, canned, and dry pellet forms. These may help provide a balanced diet, but they have not been critically evaluated and are seldom accepted as the sole diet.
Composition of Plant Foods that May Be Offered to Reptiles
Although some species will drink from a water bowl, others will only imbibe water droplets on plants and décor. Poor water quality has been implicated as a cause of stomatitis in snakes. Lack of appropriate water delivery has been implicated as a predisposing cause of renal disease in green iguanas. The advent of timer-controlled sprinkler systems or simple drip systems makes regular water provision possible for many of these more fastidious drinkers.
See also Nutrition in Reptiles.