But not all bats. Only certain bats use the cave exclusively, either roosting singly, or in dense clusters with several hundred bats per square foot of the cluster. Some bat species live in caves only during the summer, some during the winter. But some live in caves all year. Bat droppings, called guano piles, are a nutrient source for bacteria, fungi and some small animals in the caves.
Some caves contain streams and pools.
Here, salamanders flourish and the pickerel frog overwinters. Other creatures like aquatic isopods, small flatworms called planaria, crayfish, aquatic snails, fish and amphipods live in the water. Animals in the deeper part of the cave are often pink or white. These creatures are cave adapted that have been isolated from the surface for thousands of years. As a result, they have lost the ability to produce pigment in their skin, and the ability to produce eyes.