Most of these organisms reside to the area near the entrance, but some species live in the darkest reaches of the cave. Cave life may be divided into those forms living exclusively in caves and those that live in caves part of the time but forage in the open. The cave cricket and some cave fish are examples of animals modified for continuous life in caves. These animals are blind. Their organs of touch are highly developed.
Bats utilize caves for resting and hibernating purposes but forage in the open for their food.
Rich deposits of guano, or bat droppings, have accumulated over the centuries in caves where bats gather. Such detritus deposits support a variety of insects and simpler organisms. The guano is sometimes marketed as fertilizer. The number of bats inhabiting a large cave may be astoundingly large. For example, hundreds of thousands of the animals can be observed in the evening flight of bats from Carlsbad Caverns.