Earth

Miniature tigers

Because of the lack of vegetables, in the hypogeous environment the food pyramid is structured differently: the alimentary base is represented by autotrophic bacteria, which are organisms that are able to produce organic substance not from light but directly from mineral substances, such as nitrobacteria (that use nitrogen), sulphur bacteria (that use sulphur) and many others. There is a bacteriophage fauna too, that lives in mud and feeds on bacteria. Bacteriophages are in turn hunted and eaten by the limivous fauna (earthworms, crustaceans, insect larvae), that eats by sifting mud and becomes in turn prey to chilopodas (centipedes), arachnids (spiders), and insects that in caves are at the apex of the food pyramid. The “large carnivores” are represented by chilopodas and coleopterans, that, in spite of being small, have the same ecological role of lions and tigers in surface environments. Coleopterans are, of all cave animals, the ones with the most sophisticated techniques: they are efficient and terrible predators, provided with a very fine sense of smell, with a great ability to spot their prey and go great distances for food. The mouth and trophus apparatus, which is very sophisticated, leaves no escape to the prey, and makes them into the real “tigers” of the insect world. Other very efficient hunters are chilopodas and crustaceans, such as shrimp. Fish are troglobe organisms which can be larger (a few tens of centimetres), which is a sign of their position at the apex of the food pyramid in the submerged underground world.