Most tortoises and many turtles hibernate from November till March. This is not strictly necessary if they are kept indoors all year, but it corresponds to their natural way of living and strengthens their immune system. Sick animals do not go into hibernation, therefore your turtles should be checked by a vet beforehand.
Bathing them in warm water stimulates defecation and serves to prepare for hibernation. If your turtle does not gradually become quieter day by day on its own, reduce the exposure to daylight to 1–2 hours step by step over a period of 2-3 weeks. At the same time lower the ambient temperature (especially during the night).
For the actual hibernation, provide a plastic tray with damp substrate for your tortoise. For example natural coco humus or sphagnum moss are suitable for this. Turtles get a basin filled with water up to their tummies (1-2 cm high). "Store" the animals either in the cellar or in the refrigerator. A thermometer with remote sensor allows you to check that they have the optimal ambient temperature of 4-5°C. Sufficient ventilation is essential – of the tray as well as the basin.
When the animals wake up again in spring, raise the temperature step by step over 5-7 days and begin feeding them again slowly.