It is a world of total darkness, constant temperature and high humidity. The animals that live in caves must not only adapt to these conditions, they must live in an environment where there is very little to eat. The population of animals living in caves is very small compared to the animal life on the surface. Consequently, a number of cave animals are on the endangered species list. This means that they are in danger of becoming extinct.
All life depends on sunlight, even in the darkest areas of a cave.
No green plants grow here because they need light for photosynthesis. On the surface, green plants make food. Cave animals must depend on occasional floods to wash leaves, twigs and plant debris into the cave. Another food source is provided by droppings from animals that go outside to feed then return to the cave to sleep or raise their young. The droppings from animals, such as bats and crickets, may provide the only major food source in some caves.