Authentic Look, Designed For Easy Care Zilla Rock Dens satisfy a cold-blooded reptile's need for a cool burrow, in a form that offers easier care than natural rock. Ideal hiding places are cast into each den, which is finished in a realistic patina that resists bacterial growth and cleans easily with warm, soapy water. Dens are crafted of a weighty material that keeps them firm in place. Their authentic look will be equally at home in desert, forest or aquatic habitats. Choose any of the five sizes to suit small to large reptiles.