A troglobite (or, formally, troglobiont) is an animal species, or population of a species, strictly bound to underground habitats, such as caves. These are separate from species that mainly live in above-ground habitats but are also able to live underground (eutroglophiles), and species that are only cave visitors (subtroglophiles and trogloxenes).[1] Land-dwelling troglobites may be referred to as troglofauna, while aquatic species may be called stygofauna, although for these animals the term stygobite is preferable.
Troglobites typically have evolutionaryadaptations to cave life. Examples of such adaptations include slow metabolism, reduced energy consumption, better food usage efficiency, decrease or loss of eyesight (anophthalmia), and depigmentation (absence of pigment in the integument). Conversely, as opposed to lost or reduced functions, many species have evolved elongated antenna and locomotory appendages, in order to better move around and respond to environmental stimuli. These structures are also full of chemical, tactile, and humidityreceptors. Troglobites commonly do not survive well outside caves and therefore cannot travel between separate cave systems. As a result, many troglobiotic species are endemic to a single cave or system of caves.[2][3][4][5]
Not all cave dwelling species are considered to be troglobites. An animal found in an underground environment may be a troglophile (a species living both in subterranean and in epigean habitats, e.g. bats and cave swallows) or a trogloxene (a species only occurring sporadically in a hypogean habitat and unable to establish a subterranean population).[1]
No known mammals live exclusively in caves. Most bats sleep in caves during the day and hunt at night, but they are considered troglophiles or trogloxenes. However some fossorials which spend their whole lives underground might be considered subterranean fauna, although they are not true troglofauna as they do not live in caves.
^Stoch, Fabio (2001). Caves and karstic phenomena. Life in subterranean world(PDF). Italian Habitats. Udine, Italy: Italian Ministry of the Environment and Territory Protection and Friuli Museum of Natural History. Archived from the original(PDF) on 2017-08-04. Retrieved 2017-08-07.
^Culver, D.C.; Pipan, Tanja (2009). The biology of caves and other subterranean habitats. New York: Oxford University Press. ISBN9780199219933. OCLC248538645.
^Tsurnamal, M. (2008). "A new species of the stygobiotic blind prawn Typhlocaris Calman, 1909 (Decapoda, Palaemonidae, Typhlocaridinae) from Israel". Crustaceana. 81 (4): 487–501. doi:10.1163/156854008783797534.