Captive Desert Tortoise Cold Weather Care
Desert tortoises hibernate in a burrow during the winter, typically
from October through March.
Cold Weather Care
In much of Arizona, desert tortoises should be kept outdoors all year. As the weather turns cool in the fall, your tortoise will prepare to hibernate in its shelter. Its appetite will decrease and it will become less active. It will have a fat reserve built up and should easily survive through the winter hibernation using its shelter if it has eaten well during the warm months. A health check-up with a reptile veterinarian is recommended in the fall to make sure your tortoise is healthy enough to hibernate.
If your tortoise does not move into its shelter by the time temperatures at night go below 50º F, or you are not sure the shelter will remain dry during winter rains, you will need to hibernate it in a cool, dark area of your garage. If you live outside of natural range of the desert tortoise (such as Prescott), the tortoise will need to be hibernated in cool dark area inside your home (such as a closet) that, ideally, does not go below 50º F. A heavy cardboard box, non-transparent plastic storage container, or portable tortoise house packed with shredded paper or straw generally provides adequate protection. The box should be covered with several layers of blankets or newspapers, and kept up off the floor away from any holes that could lead to drafts or rodent invasion. The tortoise will not achieve metabolic hibernation if its hibernaculum is too warm.
Dehydration is a significant risk during indoor hibernation, but is generally avoided if the humidity is maintained between 30-40%. This can be monitored using an inexpensive thermometer and humidity meter. Juveniles should be offered water every 2-3 weeks, and adults every 4-6 weeks during hibernation. Otherwise, do not expose the tortoise to light or other disturbances.
Alternatively, if your tortoise does not hibernate naturally, it may be sick. Do not allow a sick tortoise to hibernate, as it may not survive the winter. If you suspect your tortoise is sick, bring it to a veterinarian. If the tortoise cannot hibernate due to a health problem or inadequate weight, the tortoise should be kept in an inside enclosure. House the tortoise in an enclosure at least 3’x3’ area. The enclosure should maintain a daytime temperature of between 80-85°F. This can be achieved by placing artificial light above the enclosure and installing a thermometer inside. Different wattages may be tried until the desired temperature is achieved. Provide food according to the summer feeding schedule or your veterinarian’s guidance and provide fresh water at least three times a week. Take the tortoise outside whenever the sun is shining and temperatures are above 70°F. Frequent exposure to sunlight is beneficial to tortoises 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. An 11-hour daylight cycle, followed by a 13-hour night cycle is ideal. As spring approaches, a hibernating tortoise will 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 April, but in particularly dry years, your tortoise may not emerge until the summer rains begin in July or August.