Well, we do use heat lamps, but the room is not staying warm enough so we had been using an electric heater on low to keep the room from freezing. I never noticed any mold growth, which I had read before using pine shaving that that is a possibility. I have not used paper towels in some time though. What substrate do you recommend then for the others? I don't have any other balls though. He was our only one. I have a king snake, corn, and red tail now. And in comparison to other balls I have seen, he was always MUCH smaller than his same aged counter parts. I always found that troubling, but just assumed him to be the "runt" of his clutch. I didn't really think that was a huge issue as many animals can be smaller than their counterparts, but I guess that maybe could have meant something was not right from the start. And she did specifially mention his lungs looked fine as I had told her about the ri he had once. I also told her that when we went to put him in the Ziploc bad that his head tipped down and liquid had come out. It wasn't discolored or thick. Seems to be water. She stated he could have drank not long before death, but never said that she found water in his lungs. He did die partially wrapped around his water dish with his head under him. I know he died in that position as his blood pooled into his upper portion, causing his mouth to appear bruised. We also worry he could have broken his neck or something on his own body or water dish, but she never mentioned finding any broken bones, which I assume she would have examined those.