Desert tortoises :
(Gopherus agassizii and Gopherus morafkai)
Desert tortoises are sensitive to the soil type, owing to their reliance on burrows for shelter, reduction of water loss, and regulation of body temperature. The soil should crumble easily during digging and be firm enough to resist collapse. Desert tortoises prefer sandy loam soils with varying amounts of gravel and clay, and tend to avoid sands or soils with low water-holding capacity, excess salts, or low resistance to flooding. They may consume soil to maintain adequate calcium levels, so may prefer sites with higher calcium content.
The desert tortoises (Gopherus agassizii and Gopherus morafkai) are two species of tortoise native to the Mojave and Sonoran Deserts of the southwestern United Statesand northwestern Mexico and the Sinaloan thornscrub of northwestern Mexico. G. agassizii is distributed in western Arizona, southeastern California, southern Nevada, and southwestern Utah. The specific name agassizii is in honor of Swiss-American zoologist Jean Louis Rodolphe Agassiz. Recently, on the basis of DNA, geographic, and behavioral differences between desert tortoises east and west of the Colorado River, it was decided that two species of desert tortoises exist: the Agassiz's desert tortoise (Gopherus agassizii) and Morafka's desert tortoise (Gopherus morafkai). G. morafkai occurs east of the Colorado River in Arizona, as well as in the states of Sonora andSinaloa, Mexico. This species may be a composite of two species.
The new species name is in honor of the late Professor David Joseph Morafka of California State University, Dominguez Hills, in recognition of his many contributions to the study and conservation of Gopherus.
The desert tortoises live about 50 to 80 years; they grow slowly and generally have low reproductive rates. They spend most of their time in burrows, rock shelters, and pallets to regulate body temperature and reduce water loss. They are most active after seasonal rains and are inactive during most of the year. This inactivity helps reduce water loss during hot periods, whereas winter hibernation facilitates survival during freezing temperatures and low food availability. Desert tortoises can tolerate water, salt, and energy imbalances on a daily basis, which increases their lifespans.
Agassiz's desert tortoise, G. agassizii
These tortoises may attain a length of 10 to 14 in (25 to 36 cm), with males being slightly larger than females. A male tortoise has a longer gular horn than a female, hisplastron (lower shell) is concave compared to a female tortoise. Males have larger tails than females do. Their shells are high-domed, and greenish-tan to dark brown in color. Desert tortoises can grow to 4–6 in (10–15 cm) in height. They can range in weight from .02 to 5 kg (0.044 to 11.023 lb). The front limbs have sharp, claw-like scales and are flattened for digging. Back legs are skinnier and very long.
Desert tortoises can live in areas with ground temperatures exceeding 140 °F (60 °C) because of their ability to dig underground burrows and escape the heat. At least 95% of their lives are spent in burrows. There, they are also protected from freezing winter weather while dormant, from November through February or March. Within their burrows, these tortoises create a subterranean environment that can be beneficial to other reptiles, mammals, birds, and invertebrates.
Scientists have divided the desert tortoise into two types: Agassiz's and Morafka's desert tortoises, with a possible third type in northern Sinaloan and southern Sonora, Mexico. An isolated population of Agassiz's desert tortoise occurs in the Black Mountains of northwestern Arizona. They live in a different type of habitat, from sandy flats to rocky foothills. They have a strong proclivity in the Mojave Desert for alluvial fans, washes, and canyons where more suitable soils for den construction might be found. They range from near sea level to around 3,500 feet (1,100 m) in elevation. Tortoises show very strong site fidelity, and have well-established home ranges where they know where their food, water, and mineral resources are.
Xerobates agassizii Cooper, 1863
Testudo agassizii Cope, 1875
Xerobates agassizi Garman, 1884 (ex errore)
Gopherus agassizii Stejneger, 1893
Testudo aggassizi Ditmars, 1907(ex errore)
Testudo agassizi Ditmars, 1907
Gopherus agassizi Tanner, 1927
Testudo agasizzi Kallert, 1927(ex errore)
Gopherus polyphemus agassizii Mertens & Wermuth, 1955
Gopherus agassiz Malkin, 1962(ex errore)
Gopherus polyphemus agassizi Frair, 1964
Geochelone agassizii Honegger, 1980
Scaptochelys agassizii Bramble, 1982
Scaptochelys agassizi Morafka, Aguirre & Murphy, 1994
Agassiz's desert tortoise in Rainbow Basin near Barstow, California
Desert tortoises spend most of their lives in burrows, rock shelters, and pallets to regulate body temperature and reduce water loss. Burrows are tunnels dug into soil by desert tortoises or other animals, rock shelters are spaces protected by rocks and/or boulders, and pallets are depressions in the soil. The use of the various shelter types is related to their availability and climate. The number of burrows used, the extent of repetitive use, and the occurrence of burrow sharing are variable. Males tend to occupy deeper burrows than females. Seasonal trends in burrow use are influenced by desert tortoise gender and regional variation. Desert tortoise shelter sites are often associated with plant or rock cover. Desert tortoises often lay their eggs in nests dug in sufficiently deep soil at the entrance of burrows or under shrubs. Nests are typically 3 to 10 inches (8–25 cm) deep.
Shelters are important for controlling body temperature and water regulation, as they allow desert tortoises to slow their rate of heating in summer and provide protection from cold during the winter. The humidity within burrows prevents dehydration. Burrows also provide protection from predators. The availability of adequate burrow sites influences desert tortoise densities.
The number of burrows used by desert tortoises varies spatially and temporally, from about 5 to 25 per year. Some burrows are used repeatedly, sometimes for several consecutive years. Desert tortoises share burrows with various mammals, reptiles, birds, and invertebrates, such as white-tailed antelope squirrels (Ammospermophilus leucurus), woodrats (Neotoma), collared peccaries (Pecari tajacu), burrowing owls (Athene cunicularia), Gambel's quail (Callipepla gambelii), rattlesnakes (Crotalus spp.), Gila monsters (Heloderma suspectum), beetles, spiders, and scorpions. One burrow can host up to 23 desert tortoises – such sharing is more common for desert tortoises of opposite sexes than for desert tortoises of the same sex.
Tortoises mate in the spring and autumn. Male desert tortoises grow two large white glands around the chin area, called chin glands, that signify mating season. A male circles around female, biting her shell in the process. He then climbs upon the female and insert his penis (a white organ, usually only seen upon careful inspection during mating, as it is hidden inside the male and can only be coaxed out with sexual implication) into the vagina of a female, which is located around the tail. The male may make grunting noises once atop a female, and may move his front legs up and down in a constant motion, as if playing a drum.
Months later, the female lays a clutch of four to eight hard-shelled eggs, which have the size and shape of ping-pong balls, usually in June or July. The eggs hatch in August or September. Wild female tortoises produce up to three clutches a year depending on the climate. Their eggs incubate from 90 to 135 days; some eggs may overwinter and hatch the following spring. In a laboratory experiment, temperature influenced hatching rates and hatchling gender. Incubation temperatures from 81 to 88 °F (27–31 °C) resulted in hatching rates exceeding 83%, while incubation at 77 °F (25 °C) resulted in a 53% hatching rate. Incubation temperatures less than 88 °F (31 °C) resulted in all-male clutches. Average incubation time decreased from 124.7 days at 77 °F to 78.2 days at 88 °F (31 °C).
A captive male Sonoran Desert tortoise with visible chin glands eats strawberries.
The desert tortoise grows slowly, often taking 16 years or longer to reach about 8 in (20 cm) in length. The growth rate varies with age, location, gender and precipitation. It can slow down from 12 mm/year for ages 4–8 years to about 6.0 mm/year for ages 16 to 20 years. Males and females grow at similar rates; females can grow slightly faster when young, but males grow larger than females.
Desert tortoises generally reach reproductive maturity at age 15 to 20 years, when they are longer than 7 in (18 cm), though 10-year-old reproductive females have been observed.
Their activity depends on location, peaking in late spring for the Mojave Desert and in late summer to fall in Sonoran Desert; some populations exhibit two activity peaks during one year. Desert tortoises hibernate during winters, roughly from November to February–April. Females begin hibernating later and emerge earlier than males; juveniles emerge from hibernation earlier than adults.
Temperature strongly influences desert tortoise activity level. Although desert tortoises can survive body temperatures from below freezing to over 104 °F (40 °C), most activity occurs at temperatures from 79 to 93 °F (26–34 °C). The influence of temperature is reflected in daily activity patterns, with desert tortoises often active late in the morning during spring and fall, early in the morning and late in the evening during the summer, and occasionally becoming active during relatively warm winter afternoons. The activity generally increases after rainfall.
Although desert tortoises spend the majority of their time in shelter, movements of up to 660 feet (200 m) per day are common. The common, comparatively short-distance movements presumably represent foraging activity, traveling between burrows, and possibly mate-seeking or other social behaviors. Long-distance movements could potentially represent dispersal into new areas and/or use of peripheral portions of the home range.
Desert tortoises can live well over 50 years, with estimates of lifespan varying from 50 to 80 years. Causes of mortality include predation, disease, human-related factors, and environmental factors such as drought, flooding, and fire.
The annual death rate of adults is typically a few percent, but is much higher for young desert tortoises. Only 2–5% of hatchlings are estimated to reach maturity. Estimates of survival from hatching to 1 year of age for Mojave Desert tortoises range from 47 to 51%. Survival of Mojave Desert tortoises from 1 to 4 years of age is 71–89%.
The desert tortoise is an herbivore. Grasses form the bulk of its diet, but it also eats herbs, annual wildflowers, and new growth of cacti, as well as their fruit and flowers. Rocks and soil are also ingested, perhaps as a means of maintaining intestinal digestive bacteria as a source of supplementary calcium or other minerals. As with birds, stones may also function as gastroliths, enabling more efficient digestion of plant material in the stomach.
Much of the tortoise’s water intake comes from moisture in the grasses and wildflowers they consume in the spring. A large urinary bladder can store over 40% of the tortoise's body weight in water, urea, uric acid, and nitrogenous wastes. During very dry times, they may give off waste as a white paste rather than a watery urine. During periods of adequate rainfall, they drink copiously from any pools they find, and eliminate solid urates. The tortoises can increase their body weight by up to 40% after copious drinking.Adult tortoises can survive a year or more without access to water. During the summer and dry seasons, they rely on the water contained within cactus fruits and mesquite grass. To maintain sufficient water, they reabsorb water in their bladders, and move to humid underground burrows in the morning to prevent water loss by evaporation.
Emptying the bladder is one of the defense mechanisms of this tortoise. This can leave the tortoise in a very vulnerable condition in dry areas, and it should not be alarmed, handled, or picked up in the wild unless in imminent danger. If it must be handled, and its bladder is emptied, then water should be provided to restore the fluid in its body.
Predation and conservation status :
Ravens, Gila monsters, kit foxes, badgers, roadrunners, coyotes, and fire ants are all natural predators of the desert tortoise. They prey on eggs, juveniles, which are 2–3 inches long with a thin, delicate shell, or, in some cases, adults. Ravens are thought to cause significant levels of juvenile tortoise predation in some areas of the Mojave Desert – frequently near urbanized areas. The most significant threats to tortoises include urbanization, disease, habitat destruction and fragmentation, illegal collection andvandalism by humans, and habitat conversion from invasive plant species (Brassica tournefortii, Bromus rubens and Erodium spp.).
Desert tortoise populations in some areas have declined by as much as 90% since the 1980s, and the Mojave population is listed as threatened. It is unlawful to touch, harm, harass, or collect wild desert tortoises. It is, however, possible to adopt captive tortoises through the Tortoise Adoption Program in Arizona, Utah Division of Wildlife ResourcesDesert Tortoise Adoption Program in Utah, Joshua Tree Tortoise Rescue Project in California, or through Bureau of Land Management in Nevada. When adopted in Nevada, they will have a computer chip embedded on their backs for reference. According to Arizona Game and Fish Commission Rule R12-4-407 A.1, they may be possessed if the tortoises are obtained from a captive source which is properly documented. Commission Order 43: Reptile Notes 3: one tortoise per family member.
The Fort Irwin National Training Center of the US Army expanded into an area that was habitat for about 2,000 desert tortoises, and contained critical desert tortoise habitat (a designation by the US Fish and Wildlife Service). In March 2008, about 650 tortoises were moved by helicopter and vehicle, up to 35 km away.
Another potential threat to the desert tortoise's habitat is a series of proposed wind and solar farms. As a result of legislation, solar energy companies have been making plans for huge projects in the desert regions of Arizona, California, Colorado, New Mexico, Nevada, and Utah. The requests submitted to the Bureau of Land Management total nearly 1,800,000 acres (7,300 km2).
A young desert tortoise
Cutaneous dyskeratosis (CD) is a shell disease of unknown origin and has unknown implications on desert tortoise populations. Observationally, it is typified by shell lesions on the scutes. Areas infected with CD appear discolored, dry, rough and flakey, with peeling, pitting, and chipping through multiple cornified layers. Lesions are usually first located on the plastron (underside) of the tortoises, although lesions on the carapace (upper side) and fore limbs are not uncommon. In advanced cases, exposed areas become infected with bacteria, fungi, and exposed tissue and bone may become necrotic. CD was evident as early as 1979 and was initially identified on the Chuckwalla Bench Area of Critical Environmental Concern in Riverside County, California. Currently, the means of transmission are unknown, although hypotheses includeautoimmune diseases, exposure to toxic chemicals (possibly from mines, or air pollution), or a deficiency disease (possibly resulting from tortoises consuming low-quality invasive plant species instead of high-nutrient native plants).
Impacts of disease :
Two case studies outlined the spread of disease in desert tortoises. The Daggett Epidemiology of Upper Respiratory Tract Disease project, which provides supporting disease research for the Fort Irwin translocation project, lends an example of the spread of disease. In 2008, 197 health evaluations were conducted, revealing 25.0–45.2% exposure to M. agassizii and M. testudineum, respectively, in a core area adjacent toInterstate 15. The spread of disease was tracked over two years, and clinical signs of URTD spread from the core area to adjacent, outlying locations during this time. Overlaying home ranges and the social nature of these animals, suggests that disease-free individuals may be vulnerable to spread of disease, and that transmission can occur rapidly. Thus, wild tortoises that are close to the urban-wildlife interface may be vulnerable to spread of disease as a direct result of human influence.
The second study indicated that captive tortoises can be a source of disease to wild Agassiz's desert tortoise populations. Johnson et al. (2006) tested blood samples for URTD (n = 179) and herpesvirus (n = 109) from captive tortoises found near Barstow, CA and Hesperia, CA. Demographic and health data were collected from the tortoises, as well from other reptiles housed in the same facility. Of these, 45.3% showed signs of mild disease, 16.2% of moderate disease, and 4.5% of severe disease, and blood tests revealed that 82.7% of tortoises had antibodies to mycoplasma, and 26.6% had antibodies to herpesvirus (which means the tortoises were seropositive for these two diseases, and indicate previous exposure to the causative agents). With an estimated 200,000 captive desert tortoises in California, their escape or release into the wild is a real threat to uninfected wild populations of tortoises. Projections from this study suggest that about 4400 tortoises could escape from captivity in a given year, and with an 82% exposure rate to URTD, the wild population may be at greater risk than previously thought.
Domestic pets :
Edwards et al. reported that 35% of desert tortoises in the Phoenix area are hybrids between either Gopherus agassizii and G. morafkai, or G. morafkai and the Texas tortoise, G. berlandieri. The intentional or accidental release of these tortoises could have dire consequences for wild tortoises.
Before obtaining a desert tortoise as a pet, it is best to check the laws and regulations of the local area and/or state. Desert tortoises may not be moved across state borders or captured from the wild. They may, however, be given as a gift from one private owner to another. Desert tortoises need to be kept outdoors in a large area of dry soil and with access to vegetation and water. An underground den and a balanced diet are crucial to the health of captive tortoises.
Management activities and spread of disease
Wild populations of tortoises must be managed effectively to minimize the spread of diseases, which includes research and education. Despite significant research being conducted on desert tortoises and disease, a considerable knowledge gap still exists in understanding how disease affects desert tortoise population dynamics. It is not known if the population would still decline if disease were completely absent from the system; are tortoises more susceptible to disease during draught conditions? How does a non-native diet impact a tortoise’s ability to ward off pathogens? What are the causes of immunity exhibited by some desert tortoises? The 2008 USFWS draft recovery plan suggests that populations of tortoises that are uninfected, or only recently infected, should likely be considered research and management priorities. Tortoises are known to show resistance to disease in some areas, an effort to identify and maintain these individuals in the populations is essential. Furthermore, increasing research on the social behavior of these animals, and garnering a greater understanding of how behavior facilitates disease transmission would be advantageous in understanding rates of transmission. Finally, translocation of tortoises should be done with extreme caution; disease is typically furtive and moving individuals or populations of tortoises across a landscape can have unforeseen consequences.
Corollary to research, education may help preventing captive tortoises from coming in contact with wild populations. Education campaigns through veterinarians, government agencies, schools, museums, and community centers throughout the range of the desert tortoise could limit the spread of tortoise diseases into wild populations. Strategies may include encouraging people to not breed their captive tortoises, ensure that different species of turtles and tortoises are not housed in the same facility (which would help to prevent the spread of novel diseases into the desert tortoise population), ensure captive tortoises are adequately housed to prevent them from escaping into the wild, and to ensure that captive turtles and tortoises are never released into the wild.
Desert tortoises have been severely impacted by disease. Both upper respiratory tract disease and cutaneous dyskeratosis have caused precipitous population declines and die-offs across the entire range of this charismatic species. Both of these diseases are extremely likely to be caused by people, and URTD is easily linked with people releasing captive tortoises into the wild. The combination of scientific research and public education are imperative to curb the spread of disease and aid the tortoise in recovery.
State reptile :
The desert tortoise is the state reptile of California and Nevada.
Human development :
Landfill proposal :
In 2006, a proposal was made in California to build a landfill in Kern County, a site near the Desert Tortoise Natural Area, to dump trash for Los Angeles residents. A landfill would attract many of the tortoise’s predators – ravens, rats, roadrunners, and coyotes – which would threaten their population.
Ivanpah solar power project :
Concerns about the impacts of the Ivanpah Solar thermal project led the developers to hire some 100 biologists and spend US$22 million caring for the tortoises on or near the site during construction. Despite this, in a 2011 Revised Biological Assessment for the Ivanpah Solar Electric Generating System, the Bureau of Land Management anticipated the loss or significant degradation of 3,520 acres of tortoise habitat and the harm of 57–274 adult tortoises, 608 juveniles, and 236 eggs inside the work area, and 203 adult tortoises and 1,541 juvenile tortoises outside the work area. The BLM expects that most of the juvenile tortoises on the project will be killed.
Conservation efforts :
The Desert Tortoise Preserve Committee protects roughly 5,000 acres of desert tortoise habitat from human activity. This area includes 4,340 acres in Kern County, 710 acres in San Bernardino County, and 80 acres in Riverside County.
In the summer of 2010, Public Employees for Environmental Responsibility filed a lawsuit against the National Park Service for not having taken measures to manage tortoise shooting in the Mojave National Preserve of California. Biologists discovered numerous gunshot wounds on dead turtle shells. These shells left behind by vandals attracted ravens and threatened the healthy tortoises.
Reptiles are known to become infected by a wide range of pathogens, which includes viruses, bacteria, fungi, and parasites. More specifically, the G. agassizii population has been negatively impacted by upper respiratory tract disease, cutaneous dyskeratosis, herpes virus, shell necrosis, urolithiasis (bladder stones), and parasites.
Upper respiratory tract disease :
Upper respiratory tract disease (URTD) is a chronic, infectious disease responsible for population declines across the entire range of the desert tortoise. It was identified in the early 1970s in captive desert tortoise populations, and later identified in the wild population. URTD is caused by the infectious agents Mycoplasma agassizii and Mycoplasma testudineum, which are bacteria in the class Mollicutes and characterized by having no cell wall and a small genome. Mycoplasmae appear to be highly virulent (infectious) in some populations, while chronic, or even dormant in others. The mechanism (whether environmental or genetic) responsible for this diversity is not understood. Infection is characterized by both physiological and behavioral changes: nasal and ocular discharge, palpebral edema (swelling of the upper and/or lowerpalpebra, or eyelid, the fleshy portion that is in contact with the tortoises eye globe) and conjunctivitis, weight loss, changes in color and elasticity of the integument, and lethargic or erratic behavior. These pathogens are likely transmitted by contact with an infected individual. Epidemiological studies of wild desert tortoises in the western Mojave Desert from 1992 to 1995 showed a 37% increase in M. agassizii. Tests were conducted on blood samples, and a positive test was determined by the presence of antibodies in the blood, defined as being seropositive.
Other and recommended websites :
Desert Tortoise (Gopherus Agassizii)
- Desert Tortoise – Gopherus agassizii
Many taxonomists split this species into two subspecies or types: The Mojave Desert populations north and west of the Colorado River tend to aggregate more toward flatlands and are considered genetically distinct from the Sonoran Desert populations.
*Original name - Xerobates agassizii
This care sheet is intended only to cover the general care of this species. Further research to best develop a maintenance plan for whichever species/subspecies you are caring for is essential.
The Desert tortoise (Gopherus agassizii) is a medium sized tortoise growing to an adult size of 22 - 38 cm (9 - 15 inches) in length. It makes its home in the desert regions of the Southwestern United States and Northern Mexico. The Desert Tortoise is listed internationally as a CITES II species and is federally listed in the United States under the Endangered Species Act. Because of their protected status, it is illegal to collect a Desert tortoise from the wild in Arizona, California, Nevada or Utah without a permit. Contact your state’s wildlife agency for information on the permitting procedure as it varies state to state. Such wild collection permits are very rarely
granted, so the only realistic way to acquire a Desert tortoise is by adopting one from a state recognized organization or to be given a hatchling from a breeding captive animal. Again, check with your state wildlife agency BEFORE you consider adopting an animal of this species as federal law protects it.
It is unlawful to touch, harm, harass or collect a wild desert tortoise. If you come upon one in the wild DO NOT PICK IT UP. When stressed, Desert tortoises expel the contents of their bladders as a last ditch defense measure. This loss of their water reserves can easily doom the animal to a slow death from dehydration. Desert tortoises are under extreme pressures in the wild. The combination of chronic upper respiratory tract disease (URTD), the explosive raven population which is believed to be accounting for the death of up to 50% of all Desert tortoise hatchlings, and habitat loss are the three major reasons for the severe population decline in wild G. agassizii.
HOUSING DESERT TORTOISES INDOORS - As there is no legal trade in Desert tortoises, it is very rare that one would be held outside its natural range. Because of this there should be almost no reason to have to house one indoors. Occasionally this does become necessary though, especially with hatchlings. In the event that outdoor accommodations are not practical, predator safe, or are environmentally unsuitable, indoor facilities may become necessary.
The most common form of indoor accommodation for small or medium sized Desert Tortoises consists of a “turtle table’. To all appearances this looks like a bookshelf unit flipped onto its back. A reasonable size habitat for a hatchling is 2 feet by 3 feet (60 cm by 90 cm); as the animal grows the size of this habitat should be increased. Into the bottom of this “turtle table” holes can be cut to allow for the sinking of food and water containers flush with the surface for easier animal access.
The water area of the habitat should be large enough to allow the tortoise to soak in if it wishes - it must also be shallow enough to protect it from drowning. Photographic developing trays work well for this with larger specimens. While it is very rare that a Desert tortoise would come upon standing water in the wild, our inability to perfectly duplicate the microclimate inside a burrow necessitates the provision of a water source. As a substrate, in the dry portion of the environment grass hay or Orchard grass hay works well. Desert tortoises are very sensitive to excess humidity and hay protects against this as it does not “hold” humidity. Grass hay also provides supplemental food. Diligence in removing wet or spoiled hay must be practiced. As an alternative to hay and to more closely mimic their natural habitat, a mixture of 50% clean topsoil without herbicides, fertilizers or other additives and 50% playsand may be used. As waste products will be more difficult to detect with such a substrate it is recommended that if using this soil mix that one replace all of it at regularly scheduled intervals such as every 6 weeks or so.
In one corner of the environment a 100W spot lamp should be positioned to provide artificial basking facilities. This should be positioned to provide a basking spot of 90 degrees F (32 C) or so in that section of the habitat. The habitat should also be equipped with a full spectrum fluorescent light to provide for UVB. A UVB source is necessary for Vitamin D3 synthesis (needed in calcium metabolism). If preferred to this lighting arrangement a Mercury vapor bulb may be used that fulfills both heat and UV requirements. While Desert tortoises can handle cool weather quite well, cold combined with wet conditions will result in respiratory distress, especially in animals that have suffered from prior cases of URTD. As they are burrowing animals they should be provided with a dark, dry retreat. There should be a hide box located in the corner away from the basking spot to provide the animal with this retreat.
OUTDOOR HOUSING - Predator proof outdoor habitats offer many advantages over indoor accommodations and should be seriously considered as an option during warm weather. Since these tortoises burrow, the perimeter should have sides extending well below the surface of the soil. This species does not do well in areas of high humidity and rainfall. If they are to be kept in such areas, provision must be made to ensure that a large portion of their environment does not become overly wet through the use of landscaping and proper drainage. Many keepers have found that it is advisable to construct an artificial burrow for their tortoises to mimic their natural environment. Some form of outdoor housing for much of the year is vastly preferred over strictly indoor housing.
DIET - A high fiber, low protein, and calcium rich diet will ensure good digestive tract function and smooth growth. Desert tortoises are prone to pyramiding or “stacking” of the scutes as well as bony imperfections. Over reliance upon 'supermarket' greens should be avoided. In general supermarket greens have been cultivated to appeal to human tastes; this tends to result in a “green” that is both high in sugar and low in fiber.
Cacti (spineless prickly pear/ opuntia pads)
Grasses (Bermuda grass or Orchard grass)
Leafy greens (dandelions, endive, grape leaves etc.)
Additional calcium supplementation is essential. Powdered calcium can be sprinkled all foods. It is suggested that one use calcium supplemented with vitamin D3 if the animal is being maintained indoors and calcium without D3 if it is outdoors. Provision of a cuttlefish bone, which can be gnawed if required, is also highly recommended not only for the calcium but also to maintain proper beak growth. Regular supplemental use of vitamins and mineral complexes is encouraged.
MEDICAL – Desert tortoises are extremely susceptible to disease, in particular URTD, which is believed to be caused by Mycoplasma agassizii. Specific tests have been developed at the University of Florida to check for this organism in your animal. If one wishes to maintain a group of CDTs, each animal should be tested in order to determine its mycoplasma status. Positive and negative animals should NEVER be mixed. It is believed by many that the URTD that is causing a massive die off of wild desert tortoises originated in captive populations that were released after contact with exotic tortoises. For further information on mycoplasma, please refer to:
This species should NEVER be mixed with any other species of turtle or tortoise. If you are maintaining animals with known respiratory disease, be sure to use extreme caution to prevent cross contamination with other chelonia in your collection.
This is a rather obstinate species and males cannot be housed with other males. Combat will ensue and if flipped over in warm temperatures, there is a good chance if this is not caught and remedied early on that the loser of the battle could expire from hyperthermia and dehydration.
This species hibernates in nature, after careful research and provision of a cool dry location this can be reproduced for your tortoise.
It should be noted that turtle and tortoise care research is ongoing. As new information becomes available we share this on the World Chelonian Trust web site at www.chelonia.org. Serious keepers find it to be a benefit to have the support of others who keep these species. Care is discussed in our free online email community, which may be joined from the web address above. Please contact us about the many benefits of becoming a member of the World Chelonian Trust.
BASIC CARE: DESERT TORTOISE
courtesy to : azeah.com/tortoises-turtles/basic-care-desert-tortoise
The desert tortoise is a threatened species throughout much of its range which includes both the Sonoran and Mojave deserts. Recently the desert tortoise was split into 2 separate species.The Agassiz's desert tortoise (Gopherus agassizi) lives in the Mojave deserts of California, Nevada, Utah, and Arizona west of the Colorado river. The Morofka's desert tortoise (Gopherus Morafkai) resides in the Sonoran deserts of Arizona east of the Colorado river and Mexico. The 2 species can interbreed and many of the captive tortoises in the Phoenix area are hybrids, which can only be determined by genetic testing.
Wild desert tortoise populations are threatened by development and destruction of natural habitat. In the meantime, captive tortoises have the opposite problem and have become over-populated. Large numbers of tortoises now sit homeless in sanctuaries throughout the southwest US. Wildlife officials are unable to return these captive to the wild because many are hybrids and there is a high risk of exposing wild tortoises to any diseases carried by these pet tortoises.
To know the current regulations, go online at or call a local Arizona Game and Fish Department office and ask for the latest regulations on amphibians and reptiles. Collecting a desert tortoise from the wild is illegal. Possession limit is one tortoise per person in a household.
Breeding desert tortoises presents a legal problem for some people. By Arizona wildlife regulation, babies tortoises must be given away by 24 months of age unless you have received specific permission to keep them longer. Starting in 2016, breeding desert tortoises is illegal in Arizona.
Size: Up to 20 pounds
Lifespan: 60-100+ years
CAPTIVE CARE REQUIREMENTS:
We recommend desert tortoises be housed outdoors whenever possible. Pens can be constructed with solid walls which the tortoises cannot see through. Tortoises will try in vain for hours to walk through fences if they can see through to the other side. The walls should extend below the ground surface a minimum of 6-12 inches to discourage tortoises from digging under the walls. The enclosure must also provide protection from predators and other family pets, such as dogs, which could harm the tortoise.
Indoor housing is only appropriate for small or sick members of this species. Young tortoises should be housed in enclosures with opaque sides for the same reason solid fencing is recommended for outdoor pens. Commercially available tortoise enclosures such as the Zoo Med Tortoise House or a terrestrial WaterLand Tub work well. However, a good sized storage container can work just as well.
Cage Size – Outdoor enclosures should be minimally 18 square feet in size for an adult tortoise.
Substrate – Natural soil (outdoors) or compacted organic topsoil are preferred. Alternatively a mix of cypress mulch and coconut fiber bedding can be used. Avoid reptile barks, wood shavings, sand, and gravel as these can be accidentally ingested and the dust they contain can cause respiratory irritation. Rabbit pellets have been used, but use caution as this substrate molds very easily. Substrates should be at least 3-5 inches deep or more to allow the tortoise to burrow.
Cage Furnishings – Shelter should be provided such as a hide or cave for indoor tortoises and an artificial burrow for outdoor tortoises. Click here to see a diagram on how to construct an artificial burrow.
If water is provided use a shallow, wide dish large enough that allows the tortoise to fully climb inside. Alternatively, water can be provided by flooding a small area of the pen or soaking your tortoise for 15-30 minutes in shallow warm water several times a week. It's preferrable to not have water available at all times for this species. Sporadic water availability encourages them to drink well and empty their bladders fully.
Use a flat dish or patio stone for a food dish to prevent the tortoise from accidentally ingesting substrate while eating.
Temperature – Daytime: 85-88°F; Nighttime: 75-80°F; Basking 95-100°F. Provide heat indoors using a heat lamp. Place the lamp off to one side of the enclosure to allow for a temperature gradient. The use of a thermometer and thermostat is recommended to assure proper temperatures.
Lighting – When housed indoors desert tortoise should be provided artificial UVB lighting to allow for proper calcium absorption form their diet. This should be provided through a commercially available fluorescent or mercury vapor reptile bulb specifically designed for this purpose. Follow the manufacturer’s instructions as far as bulb placement, typically most bulbs require the animal to be able to get within 12-18” for proper UVB exposure. Bulbs should be replaced every 6-12 months, again depending on the manufacturer’s recommendations, as they will stop producing UVB light long before they stop giving off visible light.
ortoises housed outdoors will receive all the UVB light they need from the sun.
Click here to learn more about UVB lighting.
Disinfection and Cleaning – For indoor enclosures, droppings should be removed as noted but minimally daily. Substrates should be replaced 1-2 times monthly or more if needed. Disinfect the enclosure and furnishings at least monthly using a 1 to 10 freshly made dilute bleach solution. Make sure to rinse the enclosure well with water after to remove the bleach. Drying the enclosure in the sun will also help in the disinfection process.
Outdoor enclosures should be free of visible feces which should be raked up regularly. Water bowls should be cleaned and sanitized every 2-4 weeks as above.
Desert tortoises are herbivores, meaning they eat plants. They require diets high in fiber for healthy growth and digestion. The majority of their diet should be grasses and weeds. The easiest way to provide this is to provide the tortoise with access to grassy areas where they can graze. Alternatively, grass hay can be provided, such as Timothy, Bermuda, or orchard grass hays. Edible shrubs and garden plants can also be planted in the enclosure, which many tortoises will relish. A list of edible plants is available by clicking here. Diets can be supplemented with leafy greens, fruits, edible flowers and vegetables, but it’s important to limit these items to no more than 20% of their diet as these tortoises are adapted to grazing grasses. Tortoise pellets, such as Mazuri or Zoo Med’s Grassland Tortoise, can be given occasionally. Avoid pellets with artificial colors.
Never feed your desert tortoise meat, insects, dog or cat foods, or monkey biscuits. These high protein foods will lead to shell abnormalities and kidney disease.
Dietary Supplementation – Desert tortoises housed indoors or young, rapidly growing tortoises should have their diet supplemented with a calcium carbonate powder such as ReptiCal 2-3 times weekly. More information on nutritional supplementation is available here.
This species of tortoise hibernates in colder, winter months. For more information on how to hibernate your tortoise click here.
Videos on Desert Tortoises care :
Pet Turtle Care : How to Care for a Desert Tortoise
Desert Tortoise Care
Desert Tortoise Egg-laying Behavior
Pet Turtles : How to Care for a Desert Tortoise
So You Want To Adopt A Tortoise?! TortoiseGroup.Org
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1- African Spurred Tortoise 2- Aldabra Tortoise 3- Leopard Tortoise4- Russian Tortoise 5- Sulcata Tortoise6-Red-Footed Tortoise7- Radiated Tortoise8- Pancake Tortoise 9- Hermann's Tortoise10-Marginated Tortoise11- Gopher Tortoise12- Greek Tortoise13- Galapagos Tortoise14- Elongated Tortoise15- Hingeback Tortoise16- Yellow Foot Tortoise 17- Desert Tortoise 18- Indian Star