"This cave is great for reptiles that are nocturnal and looks nice in the habitat. The small works well for leopard geckos, African fat-tailed geckos, and other land dwelling small lizards, snakes, etc. The medium might work better if you have two or more reptiles in a habitat. These are inexpensive, sturdy, easy to clean, and a great item for a reptile. To clean them you can use hot water, or a disinfectant. The hole is a perfect size so that the animal(s) can go in but you can't really see them. Highly recommended!"