(Not all tortoises are hibernating species, so double check first! The following only applies to hibernating species)
In captivity, some tortoise keepers hibernate their tortoises and some do not. But we still don’t know what the long-term effects of never hibernating them is. So if your tortoise is a good weight, is healthy, and has been with you for at least one year, then hibernation is recommended.
Hibernation temperatures should be between 3C/37F and 7C/44F, but between 4C/39F and 5C/41F is even better.
The fridge method of hibernation is the safest. With a refrigerator, you can keep your tortoise at a safe and steady temperature. You can also be sure that he is safe from other animals (rats have been known to chew on and severely injure hibernating tortoises that are not in refrigerators).
It is recommended that you use a refrigerator that does not have a freezer and that you set the refrigerator up at least a few weeks in advance to monitor it and keep an eye on the temperatures. If there is a lot of empty space in the refrigerator, fill it with bottles of water (but don’t fill it to the point that you restrict airflow). This will help stabilize the temperature.
You will need to wind your tortoise down before putting him in the fridge. Tortoises naturally slow down and eat less before hibernation, and the wind down period is basically just you helping to make that process goes as perfectly as possible.
The weekly wind down guide below is for an adult tortoise. If you have a juvenile, do all the same steps but do them over 5 days rather than over a week. If you have a hatchling under 35 gram, hibernation is not recommended.
Week 1: Stop feeding your tortoise. That may sound cruel, but it’s actually extremely important to have your tortoise’s digestive tract cleared out before hibernation. Soak him daily to help clear out his digestive tract. Keep him warm and keep his lights on for 12 hours a day as usual. This is also a good time to start setting up and monitoring your hibernation refrigerator if you haven’t already.
Week 2: Continue to not feed him. Continue to soak him every day or two. Cut his lights down to 8 hours a day. If he is still pooping regularly this week, then repeat this process a little longer.
Week 3: Continue to not feed your tortoise. Keep soaking him. Once he has stopped pooping regularly, decrease his heat and light down to 4 hours a day.
Week 4: Continue to not feed. Turn off the lights and heat. Keep your tortoise in a cool room, around 10C/50F degrees. Towards the end of the week, give your tortoise a bath and dry him off. If he does not poop, then continue on with no heat, lights, or food in the 50 degree room. After a couple of days, put him in his hibernation box. A plastic box with air holes and enough room for your tortoise to turn around is ideal. If you have multiple tortoises, use multiple boxes. Now he’s ready to go in the refrigerator. If he did poop during his last bath, then give him a few more days before putting him in his box.
During hibernation, open the refrigerator door every day to get some fresh air in there. Take your tortoise out every week to check him. Make sure his eyes and nose look clear. Make sure he’s not losing too much weight (a tortoise should not lose more than 10% of their body weight during hibernation, and any loss should be gradual). Make sure there is no swelling or other unusual signs. Make sure he moves a bit when touched.
If all looks well, quickly put him back in the fridge. Continue to open the fridge daily, and let your tortoise stay in there for up to 18 weeks.
If all does not look well, wake him up.
When you’re ready to wake him up, take him out of the fridge, but keep him in his box. Do not put him near light or heat. Instead, let him warm up gradually. Juvenile tortoises usually warm up and are ready to come out of their box after about 10 minutes. Adults take about an hour.
If your tortoise hibernated all winter with no problem, then when you take your tortoise out of his box, place him near, but not directly under, his heat lamp. Let him walk directly under it if and when he is ready to. This will be less shocking to his body, and it will also let you know that is walking normally and will therefore be able to get away from the heat when he is ready to as well. Once he has warmed up, give him a warm 20 minute bath. Bathe him twice a day for the first few days after waking up.
Food can then be offered. If your tortoise has not eaten within one week of waking him, take him to the vet.
If you will not be hibernating your tortoise, then feed him, bathe him, and keep his lights on as usual (12 hours) throughout the winter.