Tortoise Winter Hibernation: Complete Guide to Safe Brumation

Preparing land tortoises for their winter sleep can be done in various ways. Here is one proven method shared by an experienced tortoise breeder, tested and verified in personal practice! Big thanks for adding another valuable piece to the puzzle of successful tortoise husbandry.

Below is a simple guide on how to easily set up a safe hibernation box. This setup features three main advantages: first, it is simple to prepare; second, it does not mold; and third, it provides ideal conditions for the tortoises. The core secret lies in a clever material called filtering fleece / synthetic filter media.

1. Preparing the Tortoises: By the end of September, tortoises emerge near their outdoor shelter, stop eating almost entirely, and begin emptying their digestive tracts (even inside the shelter, so I change the straw roughly every three days). From mid-life in October, they move very slowly and only occasionally emerge for a short moment, hardly ever defecating. Depending on the weather, I move them into hibernation only when outdoor temperatures drop near freezing (down to max -3 °C / 26 °F). At this point, I insulate their outdoor shelter.
2. Box Foundation: Take a plastic storage box and place a 5 cm layer of washed river sand (rinsed approximately three times in water) at the bottom. Lightly moisten this sand layer with water.
3. Expanded Clay / Vermiculite: Add another layer of approximately 5 cm of expanded clay pebbles (or vermiculite). The clay will absorb and retain moisture.
4. Filtering Fleece: Prepare filtering fleece (ideally a separate piece for each tortoise). This synthetic material—commonly used in industrial ventilation units—retains moisture and, most importantly, does not mold! (I use a material approx. 1.5–2 cm thick, cutting about 2 square meters from a roll; costing around 300 CZK, it is well worth it).
5. Rodent Protection: Fine metal wire mesh with a protective coating serves as defense against mice. The mesh can be simply clamped under the lid of the box, or you can add extra security (e.g., placing the box on glass elevated by jars or inside a small terrarium) to ensure mice have no access.
6. Box Insulation: Place the plastic box inside a cardboard box or, preferably, a wooden crate, and insulate all around using suitable materials such as styrofoam.
7. Placing the Tortoises: Visually inspect the tortoises, weigh them, and place them into the box. Try to keep this process quick (when picked up from their shelter, they usually let out a loud huff or hiss).
8. Covering: Slightly moisten the filtering fleece and cover the tortoises with it. Keep the fleece damp throughout the entire hibernation period (using a spray bottle).
9. Temperature Monitoring: Insert a thermometer to monitor temperatures. A simple thermometer is sufficient. Try not to disturb the tortoises—check them visually 1× per week without picking them up.
10. Spring Awakening: In spring, when outdoor temperatures rise above freezing, move the tortoises back to their outdoor shelter (watch out for sudden late frosts!). Let the box with sand, clay, and fleece dry out in the sun, and it will be ready for the next winter.

The photos show 7-year-old marginated tortoises (*Testudo marginata*) being hibernated. I hibernate them in a cold shed—when outdoor temperatures drop below freezing, I additionally cover the box with insulating foam and a blanket, and if severe frosts below -7 °C (19 °F) arrive, I move the box into a cellar.

Final and Most Important Warning:

NEVER bathe tortoises as they are falling asleep before entering the box, nor when transferring them from the box back to their shelter in spring! Doing so would be the absolute last thing you do for them. Mortality would occur within days.

Special thanks go to the author of this guide for willingness to share personal breeding experiences. Thank you, and we wish everyone great success in tortoise keeping!

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• Testudo hermanni (Hermann’s Tortoise) Care Guide – Complete overview of keeping and breeding.
• Tortoise Incubators: Dry vs. Water-Based Systems – Learn how to build reliable hatching systems.
• Unhatched Tortoise Eggs: Candling and Identifying Bad Eggs – Practical inspection guide.
• Hatching Anomalies: Twins, Yolk Sac Issues, and Development Defects – Real-world breeding cases.