Spiders are very common in caves. Some spider species live on the surface in dark and damp places, so cave entrances make little difference. Thus, most cave spiders are troglophiles or cave-loving animals. Nevertheless, they are partly adapted to the lightless environment, for example with elongated front legs that improve the sense of touch. Since spiders feed on other insects, their occurrence is obviously limited to caves where there is a sufficient food supply. In Central Europe, these are mosquitoes and moths that spend the night or hibernate in the cave. Cave spiders are also very common in caves with larger bat colonies. The guano, food remains of the bats and also dead bats are the food basis of a whole ecosystem of insects up to spiders.