Soft-shelled turtle (family Trionychidae), Deer Cave, Borneo. Deer Cave in Borneo is the world's largest natural rock chamber. It is home to millions of bats. Their droppings collect on the cave floor and build up to huge heights. The droppings support a whole ecosystem of animals, described as troglobites, that live exclusively in the darkness of the cave. Water runs through the cave where aquatic life such as this turtle, and crustaceans exist.