I started this thread because I am concerned about my leopard tortoises whose skin has significantly changed color. I just recently changed my substrate to Coco husk and sphagnum moss that I had bought from a local pet store and it had said that it was a 100 percent natural and that was made for burrowing species. The thing that concerns me is that my leopard tortoises head changed to a brown after he had slept the whole night with his head buried in the substrate and it has stayed this color for about 3 days. I was wondering what you guys think I should do. The color looks almost like oil on his head. I have pictures atached one was before and the rest are after.