Our Russian tortoise, Ira, has been in hibernation since 19 Dec 03. This morning, we took him out of hibernation and warmed him up. Ira's hibernation adventure began in late October when he stopped eating regularly. Sarah and I stopped feeding him altogether in early November. Tortoises that hibernate with any food or waste in their digestive tract will die as the food rots in their belly during hibernation. Thus, it was very important to make sure that Ira had a completely empty system.
In addition to stopping feeding, we also started soaking Ira in luke-warm water more regularly. Soaking him ensured that he was properly hydrated. It also helped to flush any wastes out of his digestrive tract.
A thermometer was put into the fridge to check the temperature of the air. We were lucky as our fridge was right in the hibernation sweet spot of 39-41°F. On the appointed day, at the appointed hour, we cleared all the vegetables out of the vegetable crisper in our fridge. Some shredded newsprint went into the empty crisper to serve as bedding for Ira. Then, it was time to put Ira into the fridge. Right before he went into the fridge, I weighed Ira and recorded his weight and the date on a piece of paper. I put Ira into the fridge early in the morning, before he had a chance to wake up from his nightly rest.
Over the next weeks, we occasionally opened up the crisper drawer to see how Ira was doing. He was clearly in a deep sleep, but somewhat responsive to physical stimulation. About once a week I spritzed his newsprint to temporarily raise the humidity in the crisper to prevent him from becoming dehydrated. Also, I weighed Ira periodically to ensure that he didn't lose very much weight while in hibernation.
This morning, seven weeks after he went into the fridge, I took Ira out and started warming him up. After sitting in his pen for roughly fifteen minutes, he started to show some signs of wakefulness. His breathing got much deeper and more frequent. His head started to come out of the shell and orient itself towards the light. About one-half hour after taking him out of the crisper drawer, I put him in a warm bath to soak for twenty minutes. This helped to rehydrate him after spending so much time in a frost-free fridge.
Now Ira is back in his pen, basking under his heat lamp. He hasn't eaten anything yet, but I'm guessing that he is still waking up his various organs and bodily functions. However, given his clear eyes and generally quick reflexes, it appears Ira survived his hibernation adventure with no deleterious effects.