Care, Husbandry and Diet of the Desert Tortoise
Gopherus (Xerobates) agassizii Cooper

Produced by the ASDM Tortoise Adoption Program

Introduction

Desert tortoises have been kept as pets in Arizona for many decades. It is not surprising that so many people find this endearing desert denizen so appealing. Tortoises are highly personable and often appear to interact with people and other animals around them. Unfortunately, these positive qualities have become yet another threat to its existence, especially near rapidly-growing urban areas.

We generally do not believe that desert tortoises should be kept as pets, if by "pet", one means an animal which is frequently handled. Tortoises fare best when handled or disturbed as little as possible, although much enjoyment and understanding of the nature of the desert tortoise can be gained simply by observation of natural behavior. On the other hand, so many tortoises are presently held in captivity in Arizona that it would be impossible and impractical to strictly prohibit possession of them. Wild desert tortoises have been strictly protected since 1987 due to concerns about the potential for decline of their populations. Tortoises may not be collected from the wild, imported, or exported from Arizona without specific permission from the Arizona Game and Fish Department. Tortoises obtained from a captive source, however, may be kept, with one tortoise per family member allowed under Arizona wildlife regulations.

For these reasons, tortoise adoption programs have been established to help facilitate transfer of surplus or unwanted captives to custodians who are sufficiently informed and committed to provide an appropriate home for them. In Arizona, no one "owns" a desert tortoise, but people may become "custodians" to insure the welfare and longevity of those already in captivity. Because tortoises are so long-lived (80-100 years or more!), the custodial commitment may well last a lifetime. The tortoise may, as likely as not, outlive its custodian!

The Tortoise Adoption Program administered by the Arizona-Sonora Desert Museum was established to aid the welfare of tortoises already in captivity and insure the preservation of wild tortoises. The program is therefore dedicated to the well-being and survival of the desert tortoise throughout its range. However, the program only serves Tucson and its surrounding suburbs. In general, tortoises can be adopted from April 1 through September 30 of each year, subject to availability.

Diet

One of the most important aspects of tortoise care is proper diet; therefore, please follow these guidelines to insure the health and longevity of the animal(s) you care for. The old story of the tortoise and the hare is true but incomplete. Tortoises do move slowly. In fact they live slowly, but they also die slowly. Tortoises will accept many foods that are not good for them and appear healthy for years. In reality, such diets impair organ function and are cumulative, resulting in the eventual death of the animal. Tortoises have evolved by making something out of nothing. They have adapted to withstand food and water deprivation and great fluctuations in climatic conditions.

They cannot tolerate improper diets rich in fruits or animal fats. Please do not make the mistake of viewing a tortoise as if it were a child or typical pet (dog or cat.) They are reptile specialists with specific needs. The desert tortoise is herbivorous, feeding mostly on native grasses, leafy plants and flowers. For feeding a captive tortoise see the recommended tortoise diet in Appendix III.

Caution must be exercised to insure that captive tortoises cannot consume toxic landscape plants such as oleander, chinaberry trees, desert & tree tobacco, and toadstools. Do not feed tortoises lettuce of any kind as it is poor in nutrition. Hamburger or other meat, and dog, cat, or monkey foods do not provide appropriate nutritional balance and should not be offered.

Cactus fruits may be fed in relatively small amounts and only when they are in season. Native grasses and others such as Bermuda grass, dichondra, clover, or alfalfa must be planted inside the enclosure in sufficient quantity to allow daily grazing. When dark greens are offered, they should be clean, fresh, and chopped or grated into pieces small enough for the tortoise to eat. Produce foods should be served on a dish or feeding platform to prevent ingestion of gravel or sand, which can cause gastrointestinal irritation or impaction. A shallow puddle of water for drinking should be provided at least twice a week during the months of activity. A partially buried saucer or shallow trash can lid (plastic or galvanized steel) works well (be sure that the tortoise can climb in and out of it easily.) This water source should be allowed to dry up in between waterings.

Cold Weather Care

In Arizona, desert tortoises should be kept outdoors all year whenever possible. As the weather turns cool in the fall, the tortoise will prepare to hibernate.

View of a rock-encased burrow

tortoise burrow example

The appetite will decrease and it will become less active. It will have a fat reserve built up and should easily survive through the winter's hibernation if it has eaten well during the warm months. A den can be constructed above ground using concrete blocks and 3/4" plywood or half of a metal trash can. See Appendix IV for burrow construction. The structure should be covered by at least 8-12 inches of soil for insulation. Ideally, two dens should be constructed, a winter den with a southern exposure and a summer burrow with an eastern, northern or northeastern exposure (for the open end).

An alternative method of artificial hibernation is to place the tortoise in a cool, dry protected area such as a garage or storeroom. An insulated box such as a styrofoam ice chest packed with shredded paper or straw and covered with several layers of blankets or newspapers generally provides adequate protection. The box should be kept up off the floor and away from drafts and rodent invasion. The temperature should remain around 40-55°F (4.5-13°C) and the humidity range between 30-40%. These parameters can be monitored using an inexpensive thermometer and humidity meter. The tortoise will not achieve metabolic hibernation if the hibernaculum is too warm.

Hibernating tortoises should be kept in the dark, and quietly checked every week or two to see that no health problems are developing. Otherwise, do not expose the tortoise to light or other disturbances. In general, it is best to avoid moving tortoises around during hibernation. However, tortoises hibernated artificially (indoors) have a significant risk of dehydration. Therefore, animals kept indoors through the winter should be offered water, once every 2-3 weeks for juveniles and every 4-6 weeks for adults. Additionally, tortoises hibernated outdoors that choose to hibernate outside of their burrows in places that leave them vulnerable to the elements, should be moved inside the burrow. If they continually leave the burrow, they may not be healthy or there might be a problem with either the placement or construction of the burrow. Please contact the TAP for help in these cases (520-883-3062).

Winter Procedures for Tortoises in Poor Condition

If the tortoise cannot hibernate due to a health problem or inadequate weight, follow these recommendations for indoor care: house the tortoise in an enclosure at least 1 square meter in area. The enclosure should maintain a daytime temperature of between 80-85°F. (27-30°C.). This can be achieved by placing a light above the enclosure and installing a thermometer inside. A 75 or 150 watt infrared flood lamp works well for this purpose. Be sure to calibrate the floor temperature with a thermometer before introducing the tortoise. Different wattages may be tried until the desired temperature is achieved.

Provide food according to the summer feeding schedule and provide fresh water at least three times weekly. Take the tortoise outside whenever the sun is shining and temperatures are around 70°F (18°C.). Frequent exposure to sunlight is beneficial to tortoises in rehabilitation and will usually stimulate their appetite. Shade must always be available. Placing a container in full sunlight can cause the tortoise to overheat and die. 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.

Warm Weather Care

As spring approaches, tortoises become more active. As soon as the tortoise emerges, be sure to provide shallow puddles of lukewarm drinking water. It will gradually resume its warm weather routine of eating, basking and exercise. Tortoises maintained in southern Arizona are usually active by early April (this varies greatly among tortoises) but may remain or become inactive in the hot, dry summer months. Tortoises in the Sonoran Desert are most active during the summer rainy season.

The minimum enclosure size for a single adult desert tortoise should encompass at least 120 square feet. This area is large enough for a single male or up to three females. (Females should be kept in a separate enclosure from males to avoid breeding.) The enclosure can be constructed of concrete block, adobe, or other solid material. Other acceptable materials include 1"x 2" welded wire fencing or 2" poultry netting supported by rebar and sunk at least 8 inches in the ground. Wire fencing for adult tortoises should have 2" wide spacing to prevent tortoise legs and heads from becoming entangled. Enclosures for hatchlings to approximately three years of age require no more 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" poultry netting to contain hatchlings which might appear unannounced and escape through the 2" fencing. The wall should be at least 18 inches high. Desert tortoises climb well, so the shelter den or other interior structures should be at least 12 inches away from the perimeter enclosure. Tortoises will readily escape and may travel considerable distances.

Pools or ponds must be fenced off from tortoises. Insecticides, pesticides, paint and paint thinners, fertilizers and other toxic agents should never be used in or near any tortoise enclosure. Dogs may be a problem if they have access to the tortoise. Dogs can chew the tortoise shell and limbs causing serious damage.

In warm weather, it is essential that the tortoise have access to shade. A tortoise may dig a shallow depression (pallet) in the soil, usually beneath a shrub or other low-growing vegetation for shelter from the summer sun. The pallet may become a frequently used shelter site during the warm months. Water is best provided by creating a depression in the soil or using a plastic saucer with water available at least twice weekly. It should be large enough for the animal to crawl into and soak and shallow enough to allow easy exit (tortoises can drown). Tortoises will absorb water through the cloaca (located in the tail) during this process. During the summer the burrow (den) must have afternoon shade and the interior can not exceed 90°F. Otherwise the tortoise may overheat and be subject to brain damage! If one is unsure of how hot a burrow is getting, use a Minimum/Maximum thermometer to record high and low temperatures (which is usually available at a hardware store). (See the checklist in Appendix I for tortoise enclosure guidelines.)

Disease and Injury

Desert tortoises are subject to various diseases. Disease often results from opportunistic pathogens or parasites which take advantage of tortoises weakened by stress, malnutrition, or improper physical environment. Prevention of disease is best accomplished by providing the recommended physical environment, shelter features, and diet. These are the most important responsibilities of the tortoise custodian and cannot be emphasized enough!

If the custodian also keeps tortoises of different species it is critical that the desert tortoise not come in contact with those tortoises or their habitat. Very serious and potentially fatal diseases can be transmitted between species. Regular veterinary checks are recommended.

Although most tortoise pathogens are not transmissible to humans, some, like Salmonella, are. Therefore, children under five years of age and individuals with an impaired immune system should be discouraged from handling tortoises (or any reptiles for that matter.) After handling a tortoise or its fecal pellets a person should wash the hands with an anti-bacterial soap.

Tortoises are susceptible to pneumonia and other respiratory ailments. Symptoms are inactivity, runny nose, labored breathing and loss of appetite. Healthy tortoises 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 tortoises. If their presence is suspected, consult a veterinarian immediately. Symptoms are usually listlessness accompanied by weight loss and abdominal stress.

Another common problem is vitamin deficiencies. For example, symptoms of a vitamin A deficiency include swollen eyelids and nasal discharge. This can be prevented by providing the recommended diet. Tortoises are easily overdosed on fat soluble vitamins so these should be avoided unless prescribed by a veterinarian.

Sunken eyes indicate dehydration. Swollen body tissues and pasty or liquid feces indicate malnutrition or infection. Prolonged inactivity or tendency to keep the eyes closed may also be indicative of a health problem, although tortoises are normally inactive during winter hibernation or dry summer aestivation.

Sick tortoises often refuse to eat and become emaciated. A tortoise 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