Peltier cooler unit cooling for tortoise hibernation cave. The cave is built for a Russian tortoise aka fourtoed tortoise aka testudo horsfieldii. Purpose is that the tortoise can decide himself when to go for hibernation. However, testing must be carried, whether he will go to the cold cave or will the natural survival instinct drive him pursue for warmer place. This cave will give us an opportunity to test which one of these hypothesis will prevail.