There are differing schools of thought on the hibernation of tortoises. It is, of course, only the species that live in temperate climates that actually hibernate; tropical tortoises either have no rest period at all or there is a period of estivation. With regard to the European tortoises, some authors advocate artificial hibernation, but others maintain that the animals should be kept warm and active during the winter months.
Hibernating is a controversial topic among reptile veterinarians. The pet should have a thorough physical examination, appropriate laboratory tests are conducted prior to hibernation to ensure health, and the owner constructs the hibernaculum and will monitor the turtle during hibernation. Hibernation is felt to be essential for adequate reproduction if the turtle will be used for breeding. If the ambient temperature remains warm, some turtles may stop eating in the fall; many will continue feeding and skip hibernation, however. As noted, only turtles that are in good health should be allowed to hibernate. Turtles must also be allowed free access to food prior to hibernation. If an owner elects hibernation, it usually begins in the fall (Sepember or October). As the temperature drops, especially if the cage temperature is allowed to cool, the turtle may decrease its feeding. At this time, food but not water should be withheld for 1-2 weeks and the temperature kept at 70-80 °F. The turtle can then eliminate and clear its gastrointestinal tract. After this period, remove the external heat source for a week and allow the turtle to remain at room temperature (60-70 °F). The turtle can then be placed in its hibernating compartment (hibernaculum).
The hibernaculum should have dim light and the temperature should remain at 50-60°F. An occasional drop to 45°F is acceptable. Persistent temperatures above 60 °F are not cool enough for hibernation and allow the turtle to turn up its metabolism and slowly starve. Temperatures below 45 °F are detrimental as well. For the safety of the turtle, it should not be allowed to hibernate outdoors where environmental temperature and predators can't be monitored. The hibernaculum should have a foot of humid peat-based pot ting soil and a 8-15 cm layer of shredded newspaper, leaves, or hay on top, allowing the turtle to burrow. The soil should remain damp, but not wet, to prevent the turtle from dehydrating. A small water bowl should be present to prevent dehydration. As a rule, turtles will hibernate for 3-5 months. Any turtle that appears ill during hibernation should be examined. The owner should check the turtle weekly at minimum. Pneumonia may be detected; signs of this disease include nasal discharge, mucus in the oral cavity, and gurgling respiratory sounds. At the end of the hibernating period, the turtle should he placed into its regular cage and the temperature slowly warmed to the normal range over a 1-week period. Food should then be offered.
Hibernation of Land Turtles and Tortoises
Observe the following rules:
1. Bathe the turtle daily for two or three days-ten to twenty minutes each time-in water with a temperature of about 24- 26°C until it has completely emptied its intestine.
2. Then turn off the heat and light in the terrarium and set the room temperature below 18°C. Leave it this way for two to three days.
3. If this procedure reinforces the behavior described above, put the turtle in its hibernation box.
4. Weigh your pet beforehand. Smaller turtles may be weighed on letter scales. Check your pet s weight every five or six weeks during hibernation to make sure it is not suffering any harm. Keep in mind that a 10 percent weight loss during the winter rest period is normal for full-grown turtles, while young animals may lose as much as 15 percent.
5. The hibernation box should mea-sure about 70*70* 80 cm. It consists of boards "casually" nailed together so that air may enter through cracks in the sides. Fill the bot-tom of the box to a height of about 10 cm with damp (not wet) lava clinker or fired clay pellets. Layer peat moss that is almost dry but not withered, leaves, or bark chips on top of this up to a level about 10 cm from the rim of the box. Cover the box with cheesecloth or screen wire.
6. Room temperature: The hibernation box should be placed in a room where the temperature ranges from about 10-12°C.
7. Feeding: Do not feed the turtle dur-ing its winter rest period.
How Land Turtles and Tortoises Wake.
After a winter rest of three or four months, bring the turtle out of its hibernation box and put it in its hide-away in the quarantine terrarium. For the time being it will continue to rest. Then move the terrarium to a room with a temperature of about 20-22°C and wait for the turtle to emerge on its own. Several things need to be done now:
1. Bathe the animal in warm water about 24-26°C to which you have added one level teaspoon of table salt for each quart (L) of water.
2.When the turtle has drunk its fill, it can return to its terrarium. The heating and lighting should be set at the customary levels.
3. Offer your pet fresh food and water daily, even if it will not eat for the first week or so.
4. Weigh the turtle to see whether it has lost more than 10 percent of its weight.
(Books: Turtles and terrapins by Jo Cobb; Turtles byHartmut Wilke, Reptile diseases by Shawn P. Messonnier)