NATURAL HISTORY
AND HUSBANDRY OF
THE DESERT BOX TURTLE
(Terrapene ornata luteola)
Produced by the Arizona-Sonora Desert Museum Tortoise Adoption Program
The Desert box turtle belongs to the order Testudines, family Emydidae (semiaquatic turtles and their relatives), subfamily Emydinae (New World pond turtles). Box turtles are characterized by a high domed carapace (upper shell) and a plastron (lower shell) with a single hinge located behind the front legs. The toes are partially webbed, and the upper surface of the head is covered with smooth skin. Four species occur in North America, two of which are only found in Mexico.
The desert box turtle ranges from the Trans-Pecos region of Texas and southeastern Arizona south into Sonora and Chihuahua, Mexico. This species is considered a "prairie" turtle, inhabiting treeless plains and gently rolling country with grass and scattered low brush being the dominant vegetation. Due to Tucson's arid climate, we recommend against keeping non-native box turtles in Arizona.
Courtship and mating usually occur in the spring, soon after emergence from hibernation. Adult males differ from females in that they have red or orange irises (in females the iris is yellowish-brown), the first toe on the hind foot is thickened, widened, and turned in, the hind lobe of the plastron is slightly concave, and the tail is generally longer. Nesting begins in early May and extends through mid-July. Nests are generally two or more inches deep. Clutch size ranges from two to eight eggs, and incubation lasts about 70 days.
Though desert box turtles are considered omnivorous and in captivity they will eat a variety of vegetable matter, under natural conditions they are chiefly carnivorous. Insects (beetles, caterpillars, and grasshoppers) account for up to 90% of their natural food. Certain other foods (e.g., vegetable matter) are eaten in great quantity when especially abundant. Desert box turtles will also eat carrion.
Daily activity for desert box turtles consists of periods of basking, foraging, and rest that vary considerably in length, generally by environmental conditions. Foraging is generally curtailed during the hottest part of the day, resuming in late afternoon and continuing until dusk. Desert box turtles are usually more active during and after thunderstorms.
Box turtles begin to enter hibernation in October and by the end of November most or all will be underground. The turtles may use other animal burrows or dig their own burrows. Emergence from hibernation occurs in March or April.
Desert box turtles are generally easy to maintain in captivity but should not be viewed as pets in the traditional sense of the word. A custodian must provide three essential needs if box turtles are to remain healthy in captivity. These are adequate shelter, appropriate light and temperature, and an appropriate diet. Box turtles fare better when handled or disturbed as little as possible, and much enjoyment and understanding of the nature of turtles can be found through simple observation. To collect a desert box turtle from the wild is legal only with a valid Arizona Hunting License and is subject to the Arizona Game and Fish Department's wildlife regulations.
The ASDM Tortoise Adoption Program (TAP) provides an outlet for surplus and unwanted captive Desert tortoises and Desert box turtles. We would encourage anyone interested in obtaining these animals to contact the ASDM TAP hotline (883-3062) for more information. Each year several box turtles are donated to the ASDM. These animals cannot be released to the wild due to potential detrimental effects on wild populations. Captive turtles may carry parasites and pathogens to wild populations, and their addition to any natural population may disrupt the dynamic balance of the latter group. The TAP was established to help ease transfer of these animals to custodians who are sufficiently informed and committed to provide an appropriate home for them. Box turtles can live 25 or more years, so this commitment may last some time.
Captive box turtles should be offered as varied a diet as possible, including both plant and animal matter. Invertebrates, including large earthworms/nightcrawlers, crickets, mealworms, beetles and slugs, should be offered 3-5x/week. Vegetables such as collared greens, kale, cilantro, green beans and broccoli, should be offered often (at least 1x/week); whole freshwater fish, sliced beef heart and whole "pinky" mice should be offered occasionally. Low-fat canned dog food (Cycle-lite, Ken-L-Ration) may be used to replace animal matter, though the aforementioned items are preferable. Fruits and high fat foods should be avoided. Uneaten food should be removed from the turtle's enclosure. This feeding regime should be followed late spring through early fall. Generally, turtles are not fed through winter and feeding should be discontinued 2-3 weeks prior to turtles entering hibernation. Juvenile and sub-adult box turtles need a high protein diet with a 2:1 ratio of calcium and phosphorus.
In captivity it is best to provide box turtles with an outdoor enclosure that has sun and shade available throughout the day. Ample shade must be provided, since even brief exposure to the midday sun can cause fatal overheating. Adequate space allowing for a sleeping and feeding area, along with a dish of shallow water for drinking and soaking must be provided. Placing stones in and out of the dish can help provide the traction necessary for the animal to enter and exit the dish.
If your yard is not secure or will not bar potential predators from entering the yard, an enclosure should be constructed that is at least twenty-five square feet in area. The enclosure can be constructed of concrete block, adobe, or other solid material. The wall should be at least 18" high. Other acceptable materials include 1" x 2" welded wire fencing or 2" poultry netting supported by rebar and sunk at least 8" in the ground. Enclosures for hatchlings to approximately three years of age require less than 1" wide spaces to prevent escape. If you are housing sexually-mature females, it is a good idea to install an outer perimeter fence of 1/2" poultry netting (or hardware cloth) to contain hatchlings that might appear unannounced and escape through the 2" fencing. Anytime that a mesh material is used, the openings must be either too small for the turtle's head or limbs to enter or large enough that the head and limbs may enter and exit easily, otherwise the turtle may become entrapped by the fencing. Within the enclosure, perhaps the simplest refuge from the elements is a large pile of crushed bark or mulch, periodically moistened to maintain high humidity inside the mulch pile. The pile should be damp but not wet in the interior. A wooden box (turned upside down and with a door cut in one end) can be added as another hiding option.
A turtle can be kept in a large aquarium indoors, preferably only for short periods of time. In such cases dirt or a newspaper substrate may be used along with a bedding of grass, alfalfa hay, straw. Fluorescent lighting, providing an artificial source of UV radiation, (see appendix) and an incandescent, reflector floodlight (providing a "hot spot") should be installed over the aquarium without a glass barrier between the animal and the light sources.
In Arizona, desert box turtles should be kept outdoors all year whenever possible. As the weather turns cool in the fall, the turtle will prepare to hibernate. The appetite will decrease and the turtle will be less active. If the animal is healthy, it will have fat reserves and should easily survive through hibernation if it has eaten well during the warm months. An alternate method of artificial hibernation is to place the turtle in a cool, dry protected area such as a garage or storeroom. An insulated box like a Styrofoam ice chest packed with shredded paper or straw and covered with several layers of blankets or newspapers generally provides adequate protection. The temperature should remain in the upper 40's°F to the mid 50's°F and the humidity range between 30-40%. These parameters can be monitored using an inexpensive thermometer (better yet, for a little more money one can purchase a minimum/maximum thermometer) and a humidity meter (hygrometer). If the turtle is kept too warm it will not achieve metabolic hibernation, and thus will use stored fat reserves too quickly.
Dehydration is a significant risk during hibernation. Juveniles should be offered water every 2-3 weeks, and adults provided water every 4-6 weeks throughout hibernation. Hibernating turtles should be kept in the dark, and quietly checked every week or two to see that no health problems are developing.
WINTER PROCEDURES FOR INFIRM TURTLES
If the turtle cannot hibernate due to a health problem or inadequate weight, follow these recommendations for indoor care: House the turtle in an area that maintains a daytime temperature of 75-85°F (24-30°C). This can be achieved by placing a light above the enclosure and installing a thermometer inside. A 75 watt reflector flood lamp works well for this purpose. Be sure to adjust the temperature range (via moving the lamp closer to or farther from the enclosure) to the numbers stated above before introducing the turtle to the enclosure.
Provide food according to the active feeding schedule and provide fresh water daily. Take the turtle outside whenever the sun is shining and temperatures are around 70°F (18°C). Frequent exposure to sunlight is beneficial to turtles in rehabilitation and will usually stimulate their appetite. Shade must always be available. Maintain a normal daily photoperiod by turning off the light at sunset. Leaving the light on at night may result in hyperthyroidism, a glandular disorder.
Box turtles are subject to various diseases. Disease often results from opportunistic pathogens or parasites, which take advantage of turtles weakened by stress, malnutrition, or improper physical environment. Prevention of disease is best accomplished by providing the recommended physical environment, shelter features, and diet. This is the most important responsibility of the turtle custodian.
Typical symptoms of disease are: Runny nose; labored breathing; sunken eyes or swollen eyelids; loose stools; loss of appetite; listlessness; swollen body tissues; prominent bones (in head and limbs); soft shell; tendency to keep eyes closed; noticeable weight loss or gain (in a short period of time.) Consult a veterinarian immediately whenever you suspect that your turtle appears ill or has been injured.
Turtles are susceptible to pneumonia and other respiratory ailments. Symptoms are inactivity, runny nose, labored breathing and loss of appetite. Healthy turtles do not move the head and forelimbs in and out to facilitate breathing. Chronic nasal discharge or raspy breathing should receive veterinary attention. Respiratory problems are sometimes treated with antibiotics.
Parasites are also common in turtles. Symptoms are usually listlessness accompanied by weight loss and abdominal stress. If their presence is suspected, consult a veterinarian immediately. We recommend Dr. James L. Jarchow, associated with Sonora Animal Hospital (888-8988). Another common problem is a vitamin deficiency. Symptoms of vitamin A deficiencies include swollen eyelids and nasal discharge, and can be prevented by providing the recommended diet. Turtles are easily overdosed on fat-soluble vitamins so these should be avoided unless prescribed by a veterinarian. Sunken eyes suggest dehydration. Swollen body tissues and pasty or liquid feces indicate malnutrition or infection. Prolonged inactivity or tendency to keep the eyes closed may also suggest a health problem, although turtles are normally inactive during winter hibernation or dry summer aestivation.
Sick turtles often refuse to eat and become emaciated. A turtle should be referred to a veterinarian if it seems abnormally light, indicating dehydration or emaciation, or too heavy, which may indicate large bladder stones. The legs and head should appear symmetrical and bones should not be too prominent.
The condition of the fecal pellets often reflects the health of the turtle. Normal healthy feces are firm and brownish-green in color. Feces that are loose, runny, or contain mucous often indicate a health problem requiring veterinary attention.
Although most turtle pathogens are not transmissible to humans, some, like Salmonella, are. It is therefore a good idea to wash your hands with an anti-bacterial soap each time after handling a turtle or its fecal pellets. Children under five years of age should not handle box turtles (or other reptiles.)
Another potential problem, fibrous osteodystrophy, is typically evidenced by a soft shell, usually caused by malnutrition resulting from lack of a proper calcium to phosphorus ratio, sunlight, or both. This condition can be prevented by offering the proper diet and enough sunlight to turtles. Corrective measures for this condition include provision of the recommended diet and daily exposure to full-spectrum ultraviolet light.
Turtles sometimes suffer physical injury resulting in cracks or fractures in the shell. Such problems can be treated at home unless the crack is severe. Consult a veterinarian to determine whether professional assistance is necessary. The following procedures are recommended to repair minor cracks:
Cleanse the crack with sterile (boiled) water. Apply Povidone-Iodine solution (i.e. Betadine®) to disinfect the wound, cover it with a sterile gauze pad, and tape the gauze in position with first-aid adhesive or surgical tape. Place the turtle in a box lined with clean rags or paper towels. Place the box in a warm, quiet place indoors and do not disturb except to occasionally offer water (NO FOOD) during the first 24 hrs. Within a few days, it is usually safe to offer food and gradually reintroduce the turtle to its regular enclosure. It will take many months for the shell to heal, so the turtle should by handled as little as possible during this time. The wound should be checked periodically to monitor infection. Re-tape as necessary until the wound heals.
Nesting females can be quite secretive in their nesting activities and the custodian may be unaware of the eggs until they hatch. Usually, it is best to leave the eggs in the nest to hatch. However, if their location is at risk and the custodian wants to attempt to incubate the eggs, the following procedure is recommended: Gently mark the top of each egg with a graphite or wax pencil (a non-toxic crayon will do) before removing them from the nest, and be careful not to rotate them. Carefully remove each egg from the nest and place it in the incubator in the exact position in which it was laid. The slightest rotation of the egg can cause the embryo to break loose from the internal membranes resulting in death.
The simplest "incubator" is a one-gallon glass jar, filled 1/2 to 2/3's full with moistened purlite or vermiculite substrate (sterile substance available at plant nurseries), with the eggs exposed just barely above the substrate. Cover the top of the jar with clear plastic film and secure it to the jar with a rubber band. Maintain a stable temperature of 80-85°F (27-32°C). Monitor the humidity in the substrate by observing moisture formation on the underside of the plastic top. A light film of condensation is preferred, large water droplets indicate too much moisture (open top and air out for 30 minutes to remedy) and a dry lid indicates not enough moisture (sprinkle a few droplets of water on the substrate lightly-NOT ON THE EGGS).
Never remove a hatchling turtle from the egg. They generally require 2-4 days or more to fully absorb the yolk after breaking through the shell. The hatchlings may emerge with the yolk sac still attached to the plastron. This is the only food source they need until it is fully absorbed. It provides vital nutrients for the hatchling and should not be disturbed. The hatchling can be placed on clean wax paper to protect the yolk until it is absorbed.
Hatchlings can be kept in a plastic shoe or sweater box, or similar container. The container must be clean and protected from invasion by insects, especially ants. Hatchlings easily tip over onto their backs, usually by climbing against the wall or over siblings.
Hatchlings require a shallow water dish containing about 1/2" of water for drinking and soaking. The shell is relatively soft but will harden over time if the turtle has access to an appropriate diet and sunlight (or an acceptable substitute). Hatchlings eat frequently and should be provided food several times a day. The ideal diet should include: Dark greens (see adult diet above), earthworms, small crickets, diced fish and small pieces of mice (avoid large pieces of bone).
Temperature, humidity, and photoperiod can be maintained as outlined for infirm turtles above, and methods for achieving UV requirements are described in the general housing section above. Juvenile turtles must be protected from predators such as dogs, cats, and birds. Covering outdoor enclosures with poultry wire or hardware cloth will reduce these risks. Exercise caution when walking about in juvenile enclosures to avoid stepping on them.
Insecticides, pesticides, paint and paint thinners, fertilizers, and other toxic agents should never be used in or near any turtle enclosure. Juveniles are particularly susceptible to these materials. Captive hatchlings may be hibernated or kept active indoors (as outlined for infirm turtles). Some mortality may occur during this time.
