school energy&environment

Temporary and permanent guests

Biospeleologists divide cave inhabitants into 3 big categories: troglossens, troglophiles, and troglobes. These are difficult sounding names that classify animals that live by chance in a cave (troglossens) or by necessity (troglophiles), or animals that live out their entire lifecycle in a cave (troglobes). The latter have adapted so well to cave life that that they could not survive on the outside.
Unwilling visitors
Troglossens are animals that end up living in a cave by chance, possibly because they fell inside a well or in a crack or were dragged into a cave by an overflowing creek or water infiltration. They are animals that generally live on the surface and that have never adapted to actual cave life. They are doomed to a quick death in this strange environment, and if in some cases they survive it is because they receive food from external sources, and usually they settle near the entrance where there is some daylight. In any case they are unable to reproduce themselves and merely try to survive as they can. Caves often contain fossils remains of troglossen animals, that entered by chance, and man happens to be among those (such as, for instance, the famous Altamura man, in Puglia)…
Comfortable shelters 
Troglophiles are “cave friends”, animals that live generally in the daylight, but occasionally will seek shelter in caves where they look for protection from the cold, storms and excessive heat, or to hide from predators. It is the case of bats, foxes, opossums, raccoons, porcupines, small rodents, snakes and many kinds of other animals that look for shelter and a safe place to bear their young as well as storage space fo their food reserves (as many rodents do) or to hide their prey from other predators (as, for instance, hyenas and leopards do). Bats and bears live out the winter in caves and give birth to their young who will then get to know the outside world only in spring because caves offer a warm shelter to spend the wintertime. Near the entrance speleologists often find traces left by cave guests: excretions, food leftovers, prints, nests and burrows. Occasionally speleologists become involuntary sources of food and shelter to cave guests: during an exploration it isn’t unlikely that one might find a whole dormouse family peacefully wrapped up around the ropes of a rucksack left at the botton of a 90-meter deep well!
Cave animals are not always large and visible: many insects and other arthropods  (such as spiders and centipedes) or amphibians (such as frogs and salamanders) find shelter in caves and in cracks dring the colder months: during the winter time near the entrance of a cave it is easy to see butterflies, spiders, and other small “refugees” that take advantage of the warmth within. Troglophiles are animals that live on the surface, that need daylight to move about and eat food that cannot be found in caves. These guests are “opportunists” that use them as dens, for resting or as shelter for their young, but that cannot live permanently in a cave: in fact they must go out to search for food or a partner. Some of them, however, have the ability to move well in the dark such as bears and rodents. Others, in spite of needing their eyesight to move about, have developed specific systems to move in the dark, such as bats  or other types of birds that make their nests in caves: the salangane (a kind of dove that comes from South-East Asia that make nests that are considered to be very refined delicatessen food in Oriental cuisines) or the guacharo (a very strange South American bird). These animals have an “echolocation” radar-like system: they are able to emit high frequency sounds that, bouncing on obstacles or preys are then perceived by a sophisticated hearing system which allows them to put together a surprisingly precise map of their surroundings even in total darkness.
Permanent residents
Troglobes are animals that spend their entire life cycle in a cave, where they are born, live, reproduce and eat. Spanning over thousands and millions of years, they have evolved so as to adapt to life in this particular environment. They have no need to go on the outside and in many cases will  live their entire lifecycle without ever leaving the cave. Not all animal phyla are represented in this category: mammals and birds are missing. Instead we find many belonging to the Arthropods (spiders, scorpions, and pseudo scorpions, centipedes and millipedes, crustaceans, such as shrimps, and especially insects), fish and amphibians.