Adaptations of Cave Critters Activity Source: Adapted with permission by National Park Service Caves with the National Natural Landmark (NNL) designation are some of the most fascinating of the thousands of caves around the world, and each one is unique. Caves’ special features are the product of various types of rock, their geologic setting, local climate, and time. This diversity in cave environments provides unique habitats for many different species of plants, animals, and other types of organisms. [Read More]