they get burned on heat rocks because usually the heat rock is too small for the animal. If provided with a heat rock that will warm the entire animal then you should be fine. I read in an article somewhere that reptiles don't have the nerve endings to be able to feel points of heat, yet respond very well to their whole bodies heating up. And i think they tested it out, and on an appropriate sized heat source of the same temperature that was thought to cause burns, the animals moved before they were burned. So it's not high temps, but too highly concentrated hot spots that are actually the problem. Now if only I could find that article.