I have a question that goes along with this topic. I have 2 Russians in the same enclosure. I have a UVB bulb in one area and a heat lamp in the other. One of my tortoises has been fully buried for 3 days now. The other is still VERY active and hungry? I don't understand why one would be burried and the other not therefore I don't think it is a temperature or light issue. Any other thoughts?