The shelter serves an important function in protecting the tortoise from the extreme heat and dryness of the summer, and providing a place to hibernate in the winter. It is important that you build a shelter that is well-insulated. Insulation can be provided by adding soil to the top, sides and bottom of the shelter. In the wild, desert tortoises prefer snug shelter, and they like to wedge themselves into a corner near the back; don’t make the shelter too roomy.
When building the shelter, keep in mind that orientation (which cardinal direction the burrow entrance is facing) affects burrow temperature. North and northeast facing shelters tend to be cooler, and provide a good refuge from summer heat. Optimal temperature range for the shelter is 68-85°F during the summer, and between 50-68°F in the winter. Shelter temperatures should always be kept below 90°F because a tortoise can overheat and suffer brain damage. During mild weather, your tortoise may dig a shallow depression (pallet) in the soil, usually beneath a shrub or other low-growing vegetation. South facing shelters warm up quicker than north facing shelters, and offer a suitable winter hibernaculum. By providing more than one shelter for your tortoise, you give the tortoise the option of either a warmer or cooler environment at different times of the year. Our recommendation is to provide multiple shelters with different orientations for each season, but a single shelter will suffice if strategically placed. If you have only one shelter for your tortoise and wish to offer it a second one, build it in the shade of a shrub or tree.
Shelters can either be stationary, meaning they remain in place year around, or portable, meaning easily moved to take advantage of either shade (in the summer) or sun (in the winter). Stationary shelters can be constructed out of a 5-gallon bucket or large metal trash, or cinder blocks (covered with a ceramic tile backer board). A bucket or trash can needs to be cut in half and placed lengthwise so that it sits level on the ground. If opting for cinder blocks, arrange 6 blocks into a “U” shape, and cover with a piece of ceramic tile backer board (e.g., Hardieboard™) or a piece of flat rock such as flagstone. For either stationary shelter, rocks can be placed around the sides and back to prevent erosion8” layer of soil added on the top, sides, and back for stabilization and insulation. The portable tortoise house can be constructed out of plywood that sandwiches foam core insulation. The portable tortoise shelter does not need to be covered with soil, and would be ideal for those in areas where tortoises must be hibernated indoors, as it can be simply carried inside the garage or the house. Shelters can be incorporated into your existing landscaping, and can be the focal point of the backyard or they can be inconspicuous, depending upon your preference.
The shelter should be in a high and dry spot, above the flood line or away from areas where water collects after rains. You can construct a flattened mound of dirt (8” high) to build or set the shelter on, which will protect the shelter from runoff. It is critical that the tortoise shelter stay completely dry
during rains. A damp shelter will cause your tortoise to become susceptible to various respiratory ailments that require costly veterinarian treatment. These ailments, if left untreated, will most likely result in the death of your tortoise.
If you opt for a permanent shelter, the type of shelter you construct for your tortoise will depend on where you live, because of differing climatic conditions found throughout the state. Because of greater rainfall, and the increased likelihood of flooding, if you live in Phoenix or Tucson, the shelter you provide should be above ground. You can find detailed instructions and photos for creating shelters in Phoenix, Prescott, and Tucson here.
If you live in Bullhead City, Kingman, Lake Havasu, or Yuma, the shelter should be dug below ground to offer the best thermal protection due to the extreme heat in these regions, and have an eave to keep rain from falling in it. However, it should still be built in a high area of your backyard enclosure to prevent flooding during heavy rain. You can find detailed instructions and photos for creating shelters in Bullhead City, Lake Havasu, Kingman, and Yuma here.