Proper husbandry is critical to the successful maintenance of reptiles in captivity. A number of thorough reviews of chelonian husbandry have recently been published.^1-4 Strict attention must be paid to environmental temperatures, humidity, light quality, water quality, habitat complexity, and nutrition. Among the hundreds of turtle species, husbandry requirements vary extensively. Prospective turtle owners must familiarize themselves with the requirements of the specific species with which they wish to work prior to purchasing the animal.

The keeper must be sure that the species can legally be kept according to state, federal, and international law. Laws pertaining to the sale and ownership of pet reptiles vary tremendously among different states and cities. Information on the legal status of species at the state level may be obtained from state fish and wildlife departments.

Many reptile species have become threatened due to habitat loss and collection for the international food, skin, and pet trade. As such, the pet owner ethically should avoid keeping animals that have been collected from the wild. In addition to ethical concerns, wild-caught animals should be avoided as they are less likely to adapt to a captive lifestyle and more likely to be harboring parasites than captive-bred animals.

In selecting a species as a pet, one should investigate those that are being bred in captivity in significant numbers and that have demonstrated longevity in captivity similar to that in their natural environment. Consideration should be given to the adult size of the species. For example, although the African spur-thighed tortoise (Geochelone sulcata) is a friendly, hardy, inexpensive, captive-bred species, it is one of the largest tortoise species in the world and cannot be humanely housed as an adult in the home of the average pet owner.

The following list of species includes those that are generally captive bred, and have proven in the author's experience to make good pets. This list is not meant to be all inclusive, but rather a starting point for the novice keeper. Among land tortoises, redfoot tortoises (Geochelone carbonaria), Greek tortoises (Testudo graeca), and Russian tortoises (Testudo horsfieldi) make good pets. Among water turtles, painted turtles (Chrysemys picta), Reeve's turtles (Chinemys reevesii), and the New Guinea red-bellied turtles (Emydura subglobosa) are personable and relatively easy to care for.

Reptile specialty pet stores often carry a wide range of healthy, captive-bred specimens. In addition, the keeper should investigate classified advertisements in reptile pet magazines. Often, local breeders may be found through these advertisements and may allow the purchaser to handpick their animal. Direct contact with a breeder provides invaluable information on husbandry of the species. Other sources for captive-bred reptiles include numerous regional reptile shows, reptile web sites, and large-scale national reptile breeders.

As ectothermic animals, reptiles must be able to move among various temperature zones to maintain their preferred body temperature. Inadequate temperatures promote poor immune response and poor digestive efficiency, and are a common cause of illness. One of the simplest heat sources is incandescent lighting in a reflector fixture that focuses heat into certain areas of the environment, simulating the heat derived in the wild from the sun. Temperatures below these lamps must vary with the ecology of the species. For example, savannah tortoises may seek basking temperatures of 32–35°C, while some leaf-litter forest species may prefer to be at 20–25°C. In addition, some species must be kept very warm even at night, while others prefer a night temperature drop. Nighttime low temperatures should be maintained at 23–27°C for tropical species and 21–23°C for temperate species. In cases where night temperatures must be high, ceramic radiant heat emitters or heat panels may be installed to provide heat without providing light. Using light-emitting heat sources at night may adversely affect the animal's sleep cycle, immune response, and reproductive cycle.

Water heaters, such as those used in tropical fish tanks, may be useful to maintain stable background temperatures in aquatic environments. In general, temperatures from 25–28°C are adequate depending on the species. Since these heaters are often made of ceramic or glass, one must ensure that they are located so that they cannot be broken by the turtles.

Most aquatic turtles need to be able to dry themselves completely while basking. Nonabrasive basking sites such as cork bark or driftwood should be available.

The choice of enclosure will vary by species. Many small species can be maintained in traditional glass terrarium setups. The enclosure must be escape proof for the kept species. Larger specimens may need to have custom-built enclosures or large, commercially available enclosures. Large aquatic species need large pools such as those used in the aquaculture industry, and generally need some type of powerful filter system to maintain adequate water quality. A very effective filter system can be constructed using a pond pump, foam or mesh filter material, and a material such as lava rock to create surface area for biological filtration. In its simplest form, the pump is used to move water from the enclosure, through the foam, over the lava rock, and back to the enclosure. In this author's experience, tap water seems to be safe for most aquatic turtles, although more conservative keepers may prefer to use aged tap water, bottled water, or reverse osmosis purified water.

Indoor enclosures offer more safety and better climate control, while outdoor enclosures offer improved ventilation and exposure to natural sunlight. Both indoor and outdoor enclosures must be made predator proof. Outdoor enclosures for small chelonians must include a secure, wire bottom and top. The bottom may be covered with several inches of dirt and planted with grass creating an escape-proof enclosure. Where fire ants are a problem, appropriate control measures should be taken. Consider mammalian pets, especially dogs and ferrets, to be a threat to small chelonians that are maintained indoors. Enclosure substrate should be easy to clean and not harmful if ingested. Gravel, sand, crushed walnut shells, and corn cobs are indigestible and may cause intestinal obstructions if ingested. Safer alternatives include newspaper, artificial turf or carpeting, paper towels, soil, hay, sphagnum moss, coconut fiber, or bark mulch. In dry environments, alfalfa pellets such as rabbit food can be used as bedding. Substrates should be spot cleaned daily and replaced when heavily soiled.

Many terrestrial turtles and tortoises will drink water from a shallow bowl. Spraying may also be required to maintain adequate humidity levels for tropical forest species. Areas of high humidity should be available, as even arid zone species will seek out such areas. Small plastic food-storage containers can easily be modified to provide high-humidity retreats. Recent evidence indicates that the commonly seen condition of "pyramiding," where the scutes of tortoises develop a conical appearance, may be caused by low environmental humidity.⁵

In addition to basking lights, full-spectrum lighting with ultraviolet B wavelengths is thought to be important for many species. Recent research has shown that UV exposure resulted in higher vitamin D levels in young red-eared sliders (Trachemys scripta elegans). The best source of UVB light is unfiltered natural sunlight. It is ideal to have an outdoor enclosure that can be used during mild weather. In the absence of natural sunlight, fluorescent or mercury vapor UVB-emitting bulbs should be provided. The lights should be located at a distance as specified by the manufacturer. UVB light is filtered out by glass or plastic, and UV intensity of most bulbs is reduced after 6–12 months of use.

Chelonians may be carnivorous, omnivorous, or herbivorous. Carnivores may accept earthworms, fish, killed rodents, insects, and commercial turtle pellets. Herbivores require a high-fiber, high-calcium diet and should be fed greens such as kale, collards, endive, escarole, dandelion, clover, chicory, beet greens, and Swiss chard. High-fiber sources such as alfalfa pellets, chopped hay, and grass are also desirable. The concern about excessive levels of oxalates and thiocyanates in some greens has likely been overstated, and these greens are appropriate for chelonians as part of a balanced diet. Omnivores may be offered a mix of the carnivore and herbivore diet. In general, fruits are not tremendously nutritious and should be used as "dessert" in small amounts.

Unless whole rodents or fortified pellets are being consumed, vitamin and mineral supplementation may be needed. In particular, insects and plant matter are often deficient in mineral content. Reptiles that are not supplemented often suffer from calcium deficiency. Supplementation may be done by mixing a powdered calcium supplement with the food items, or by feeding insects a high-calcium diet for several days before they are fed to the reptile ("gut loading"). Supplements should be used in moderation as oversupplementation can also occur. Multivitamin supplements, in particular, are often excessively high in Vitamin A and D and should generally be used only once weekly.

Physical examination of chelonians should be conducted systematically, ensuring that each major organ system is assessed. Excellent accounts of chelonian medical evaluation have recently been published.^3,4

Small turtles should be weighed with an accurate gram scale. Larger turtles may be weighed using kilogram scales. Turtles should feel dense when picked up, similar to a rock of equal size. They should be reactive. They should protect themselves by withdrawal into the shell, or demonstrate a bright, alert, active posture. Underweight turtles may feel "empty" when picked up.

The head and limbs may be difficult to extract for examination. Experience, patience, and/or sedation may be required to perform a thorough examination. The limbs are palpated for muscle mass, strength, joint swelling, and bone structure. The nails are examined for overgrowth, hyperkeratosis, etc. The skin is examined, specifically assessing the neck, axilla, and pre-femoral regions for ticks, leeches, and fly larvae. The skin may show signs of hyperkeratosis, flaking, etc. in long-term captive turtles kept on suboptimal diets. The cloaca is examined for evidence of inflammation, diarrhea, etc. Some species can emit a foul odor when disturbed. In some cases the odor is produced by glands along the bridge of the shell. Turtles and tortoises will often defecate and urinate during examination. Use appropriate care, and save these diagnostic specimens for analysis.

In sexually mature chelonians, males often have a longer tail with the cloacal opening at or beyond the caudal carapace margin. Males of many species have plastron concavity to facilitate copulation. These rules do not hold true for all species, especially for plastral concavity, and other species-specific traits may be noted. For example, sexual dimorphism may be seen in the eye or skin color, adult size, or toenail length of some species. Common examples include the red iris of male eastern box turtles (Terrapene carolina carolina), elongated toenails on the forelimbs of male slider turtles (Pseudemys spp., Trachemys scripta), painted turtles (Chrysemys picta), and map turtles (Graptemys spp.), dramatically larger female vs. male body size in map turtles and diamondback terrapins (Malaclemys terrapin), and more prominent mental glands, gular scutes, and body size, in male desert tortoises (Gopherus agassizii). If desired, gender determination of juvenile turtles may be accomplished by coelioscopic examination of the gonad.

Respiratory exam includes assessment of respiratory rate, effort, and quality. Respiratory movements in most turtles are generated by slight to moderate rotational movement of the forelimbs and/or extension of the hind limbs. Pharyngeal pumping in most species has olfactory rather than respiratory function. Respiration should be silent or slightly audible and the mouth should be closed. Gasping, loud whistling, etc. is abnormal, and may be a sign of rhinosinusitis or pneumonia.

The shell is examined for shape, symmetry, color, and density. Several species, including soft-shell turtles (several genera) and pancake tortoises (Malacochersus tornieri) have flexible shells. Several genera have normal plastron or carapace hinges that allow shell mobility. It is useful to palpate each scute, or keratin plate, of the shell, assessing for loose scutes, sensitivity, fluid, etc. Ecchymoses or petechiae of the shell may be indicative of osteomyelitis, sepsis, or spirorchid trematode infection. Soft areas of the shell may be due to infection or secondary hyperparathyroidism. Long-term captive box turtles on suboptimal diets seem to develop a rounded, ball-shaped shell, rather than the normal flat plastron and domed carapace. In these turtles, the limbs and head often seem disproportionately large in comparison with the shell, and the soft tissues of the limbs, pelvis, and neck being exposed more than in a normal specimen.

Neurologic examination is conducted using standard principles. Observe the turtle walking around the exam room if cooperative. If possible, aquatic turtles should be observed while swimming. Abnormal buoyancy is common, and often indicates pulmonary, gastrointestinal, coelomic, neurologic, or metabolic abnormalities. Proprioception, withdrawal reflexes, cranial nerve examination, etc. should be performed. Cardiac auscultation is difficult, but the heart rate, rhythm, and quality may be assessed with a Doppler monitor placed over the carotid artery or heart base. Use of Doppler monitor in the examination room is impressive to the client, and demonstrates a thorough examination. Coelomic palpation may detect eggs, bladder stones, masses, and organ enlargement. Palpation is accomplished via the prefemoral space. Depending on the size of the turtle, a single finger, multiple fingers, or the entire hand may be able to fit into the prefemoral space. The hind limb will need to be positioned in extension. Use caution in strong chelonians that may be able to crush one's fingers by withdrawing the hind limbs. In most cases, palpation will reveal only soft tissue.

The author prefers to examine the structures of the head as the last part of the examination, as the turtle is often significantly upset after head restraint, and may not allow further examination. Examination of the head is very important since many pathologic conditions affect the ears, eyes, nasal cavity, tongue, and oral mucosa. Restraining the head and opening the mouth requires some practice. Restraint of the head should not be done without sedation in dangerous species such as snapping turtles. In some cases, many of the structures of the head can be partially examined prior to restraint of the head (e.g., eyes, nares). Ideally, the examiner patiently waits for the turtle to extend its neck, and then the examiner's thumb and index finger are swiftly moved to grasp the turtle's neck behind the jaw. The examiner's hand should come from behind the head to prevent the turtle from noticing the imminent restraint. It may take significant strength to maintain control of the head, and it may be helpful to brace the remaining fingers of the restraining hand against the anterior margin of the carapace. An alternate method of initial head restraint is to grasp the head with thumb and index finger on top of the head and between the rami of the mandible. This grip does not allow examination of the mouth, but can be used as a transitional hold prior to restraining the turtle behind the head. If head restraint is not possible because the turtle refuses to extend its neck, several options are available. In some cases, "tickling" the hind feet or tail of the turtle may cause it to extend the neck. Alternatively, placing the turtle on a flat surface for several minutes, or placing the turtle in shallow water may be helpful. Rocking the turtle side to side or front to back, while held in ventral recumbency may also help. If none of these techniques work, a curved-tip dental hand-scaler may be placed under the tip of the upper beak and carefully used to slowly and smoothly extract the head. In sea turtles, the head cannot be withdrawn and is easily accessible. After failing all of these methods, sedation may be considered.

Once the head is restrained, the eyes should be assessed for signs of inflammation, discharge, corneal ulcers, etc. Vitamin A deficiency, viral infection, and bacterial infection are common causes of inflammation of the eyes. Saline eye-wash solution may be useful to flush debris. Enophthalmia may be indicative of dehydration or cachexia. There is no external ear canal in turtles. The tympanum is just deep to the skin, and should be located by palpating for a soft spot on the side of the head. Asymmetry of the tympanum may be noted with otitis media. The nares should be examined for asymmetry, discharge, etc. since rhinosinusitis is common in chelonians. The keratin of the beak can become overgrown, and conditions such as prognathism may be seen. Turtles do not have teeth. Oral examination is performed in most cases with the head restrained. However, oral examination can sometimes be performed without head restraint. Some turtles will open their mouth as a defensive display. In small sea turtles, some smaller species, or weak individuals, the mouth can often be opened by putting gentle ventral traction on the mandible, or by gently pulling the pharyngeal skin ventrally. If this is not successful, a tool is inserted along the edge of the mouth. As the turtle begins to open the mouth, the tool is quickly and smoothly repositioned transversely across the mouth. A number of tools will work well for this technique, but the author prefers a flat, stainless steel, dental spatula. Pen caps, blunted needles, dental scalers, etc. may also be used. In the author's opinion, tongue depressors do not work well for opening turtle mouths.

Once open, the oral cavity is examined for mucus membrane color, mucosal plaques, glossitis, stomatitis, etc. Oral plaques have been reported in association with herpes virus and iridovirus infection of chelonians, and warrant biopsy for histopathology and molecular diagnostics. The glottis is located at the base of the tongue and should be examined for discharge. The paired choanae are located along the palate and should be evaluated for symmetry and discharge. Occasionally, discharge from the eustachian tubes may be visible in the caudal pharynx in cases of otitis media.

In some cases, chemical immobilization may be required for thorough physical examination of chelonians.

References

1.  Gurley R. Keeping and Breeding Freshwater Turtles. Ada, OK: Living Art Publishing; 2003.

2.  Highfield A. Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles. London: Carapace Press; 1996.

3.  Mader DR, ed. Reptile Medicine and Surgery. 2nd ed. St. Louis, MO: Elsevier; 2006.

4.  McArthur S, Wilkinson R, Meyer J, eds. Medicine and Surgery of Turtles and Tortoises. Cambridge, MA: Blackwell Science Ltd; 2004.

5.  Wiesner CS, Iben C. Influence of environmental humidity and dietary protein on pyramidal growth of carapaces in African spurred tortoises (Geochelone sulcata). J Anim Physiol Anim Nutr. 2003;87:66–74.