Avoiding Crowding, Stress, and Planning For Compatibility among Your Desert Tortoises
Stress may or may not be obvious but when present is known to predispose organisms of all kinds to disease.
Area
We recommend a minimum area of 1250 sq. feet (for example 25 x 50 ft.) for one or two adults or several small juveniles which need more area than you might suppose. Beyond that, it is not so much the amount of space in your yard as how it is arranged and how well it meets the needs of the tortoises. Consider how many children share the area? What other play activities take place in the yard? Is the tortoise in danger of being stepped on or tripped over during activities by people? Are there places to bask on a dry surface at any time of day? Is there growing vegetation to eat? Is the female constantly being courted by the male?
Burrows and other Coversites
Expect your tortoise to spend approximately 95% of its life in coversites (burrows and other places to head in snugly). In order for the tortoise to function properly and remain healthy it must be free to move in and out of various temperature situations in order to regulate its body temperature.
In the average size yard, as a rule of thumb, allow at least one burrow per tortoise of a given size; more, for tortoises less than 3″ in shell length. Most burrows should be one tortoise width and several times the body length of the tortoise using it. See the Tortoise Group booklet, Desert Tortoises Adoption and Care for recommended burrow sizes for various tortoise sizes. Are there also semi-sheltered places such, as shrubs or low overhangs, all where the soil remains dry? Dog houses are not adequate shelter in the desert. Soil that is at least 12″ deep should cover the tortoise at the far end of the burrow.
For small tortoises there should be enough small burrows distributed over the yard that any juvenile is within easy reach of a burrow. Hatchlings and other small tortoises heat up quickly and may overheat before reaching shelter. Create “pathways” for small tortoises so they do not have to climb through grass or rock cover to reach burrows, water, and eating places.
Individuals show preferences for particular coversites and as temperatures change, preferences change. Some tortoises use the same cover site for most of the year, moving to another to hibernate; others, change frequently. Most burrows are used by one tortoise at a time. If you find several tortoises crowding into one burrow, creating traffic problems for the ones farthest inside, build another of the same length and facing direction. Why all this attention to shelter? Probably the most important adaptation that allows tortoises to live in the desert is their behavioral tendency to find or create a burrow that will prevent death from the lethal temperatures above ground. The tortoises’ preferred body temperature is lower than that of human beings!
With the above needs in mind you can understand that a child’s plastic wading pool or a terrarium is not large enough for even a hatchling to move about normally; to have soil deep enough for the burrow to protect the tortoise from both heat and cold; and is not large enough to grow food that will always be available and not dampen the burrow.
Fighting
Crowding in your yard is as much a matter of sizes and sexes of tortoises as it is a matter of numbers. Males raised together without females may be compatible but may start to fight as they become sexually mature or when a female is added to the group. Expect adult males to fight among themselves if kept in a yard. If this occurs, they should be separated permanently. In the desert there is room for males to move far away from one another after a brief encounter. Don’t expect a “large” back yard to prevent fighting among males if they can see one another. Forcing fighting males to remain together is inhumane. Injury and the common maggot infestation of wounds can kill. When ambient temperatures are high, a tortoise that has been flipped on its back and cannot right itself will soon die of overheating.
Fighting and courting involve chasing, shoving, and biting, but fighting, that may occur among males, females or even between a male and female, will also include attempts to overturn the other. Sometimes, a male or female that has lived alone for a long time will not accept another tortoise of any size or sex.
Fighting may occur several times a day. Be watchful. Even when fighting seems to have ceased, the submissive tortoise (underdog) may run away when it sees the dominant tortoise. It may stop emerging from the burrow to feed or bask; may refuse to eat even when pulled from the burrow and offered food out of sight of the dominant tortoise. We have observed many such cowed tortoises develop upper respiratory tract disease and die within a few weeks.
The most common conflict and the strongest reactions occur between adult males. When a new male is introduced, he, not the resident male, is apt to become the dominant one; regardless, you must prevent conflict by separating the males permanently.
Fence-pacing
Another sign of crowding is persistent fence-pacing. When a new tortoise is introduced, it tends to check the boundaries of the yard and may attempt to climb out. This behavior usually subsides within a few days if there is adequate space, shelter, and food and no conflict with other tortoises. If restlessness continues or the tortoise becomes withdrawn, and refuses to eat, these are signs of stress. Of course, if there are adult males sharing the yard, even when no fighting has been observed, indications of persistent desire to escape should be heeded. Fence pacing is sometimes seasonal. If it persists, whatever the reasons, stress is a natural consequence. If the bottom 18″ of the fencing or the gate allows the tortoise to see through, this is a frustrating and stressful situation for the tortoise. Pacing and attempts to get through can be expected. See the care booklet for ways to eliminate the frustration and potential injury from see-through fencing.
Uncontrolled Reproduction
Another cause of crowding is from uncontrolled reproduction. If hatchlings and other small juveniles do not have enough easily accessible burrows that are just their size, the need for shelter will force them to go inside a burrow used by a larger tortoise and they may be crushed, inadvertently.
Reproduction in captivity tends to be very successful. Finding good homes for hatchlings is not easy. Giving hatchlings to children or other persons who are not prepared is a common but irresponsible action. Think seriously of practicing the only kind of birth control practical at this time-permanently separate the male from the female(s). If the yard is not large enough for this, giving away the adults necessary to eliminate breeding is the humane thing to do. Responsible pet ownership by curtailing reproduction now extends to tortoises.
