A troglobite (or, formally, troglobiont) is an animal

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

, 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

trogloxene Trogloxenes or subtroglophiles, also called cave guests, are animal species which periodically live in underground habitats such as caves or at the very entrance, but cannot live exclusively in such habitats."Cave Plants and Animals". 9 December Am ...

s). Land-dwelling troglobites may be referred to as

troglofauna Troglofauna are small cave-dwelling animals that have adapted to their dark surroundings. Troglofauna and stygofauna are the two types of subterranean fauna (based on life-history). Both are associated with subterranean environments – troglofaun ...

, while aquatic species may be called

stygofauna Stygofauna are any fauna that live in groundwater systems or aquifers, such as caves, fissures and vugs. Stygofauna and troglofauna are the two types of subterranean fauna (based on life-history). Both are associated with subterranean environments ...

, although for these animals the term ''stygobite'' is preferable. Troglobites typically have

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

ary

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

s to cave life. Examples of such adaptations include slow

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

, reduced energy consumption, better food usage efficiency, decrease or loss of eyesight (

anophthalmia Anophthalmia, (Greek: ἀνόφθαλμος, "without eye"), is the medical term for the absence of one or both eyes. Both the globe (human eye) and the ocular tissue are missing from the orbit. The absence of the eye will cause a small bony orbi ...

), and

depigmentation Depigmentation is the lightening of the skin or loss of pigment. Depigmentation of the skin can be caused by a number of local and systemic conditions. The pigment loss can be partial (injury to the skin) or complete (caused by vitiligo). It can be ...

(absence of

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

in the

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

). Conversely, as opposed to lost or reduced functions, many species have evolved elongated

antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

and locomotory appendages, in order to better move around and respond to environmental stimuli. These structures are also full of

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...

tactile Tactile may refer to: * Tactile, related to the sense of touch * Haptics (disambiguation) * Tactile (device), a text-to-braille translation device See also * Tangibility, in law * Somatosensory system, where sensations are processed * CD96 CD ...

and

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

receptors Receptor may refer to: *Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a n ...

. Troglobites commonly do not survive well outside

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s and therefore cannot travel between separate cave systems. As a result, many troglobiotic species are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to a single cave or system of caves. 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 Epigeal, epigean, epigeic and epigeous are biological terms describing an organism's activity above the soil surface. In botany, a seed is described as showing epigeal germination when the cotyledons of the germinating seed expand, throw off th ...

habitats, e.g.

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

s and cave swallows) or a

(a species only occurring sporadically in a

hypogean Hypogeal, hypogean, hypogeic and hypogeous (; ) are biological terms describing an organism's activity below the soil surface. In botany, a seed is described as showing hypogeal germination when the cotyledons of the germinating seed remain n ...

habitat and unable to establish a subterranean population).

Flatworm The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegment ...
s

*''

Hausera hauseri ''Hausera'' is a subterranean genus of planarian from Brazil. It contains only the single species ''Hausera hauseri''. It is the first cave-dwelling member of the suborder Cavernicola to have been observed in South America. Etymology Both th ...

Mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

Tumbling Creek cavesnail The Tumbling Creek cavesnail (''Antrobia culveri'') is a species of freshwater cave snail with gills and an operculum, an aquatic gastropod mollusk in the family Amnicolidae.Bouchet, P. (2014). Antrobia culveri Hubricht, 1971. Accessed throug ...

(''Antrobia culveri'') *

Cave physa A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea c ...

(''Physella spelunca'') *

Phantom cave snail The phantom cave snail or phantom cavesnail (''Pyrgulopsis texana'') is a species of very small freshwater snail with an operculum, an aquatic gastropod in the family Hydrobiidae. Distribution This species is endemic to the lower Pecos Rive ...

(''Cochliopa texana'') *

Mimic cavesnail The mimic cavesnail, scientific name ''Phreatodrobia imitata'', is a species of very small or minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.Hershler R. & Thompson F. G. (1990). "''A ...

(''Phreatodrobia imitata'') * ''

Zospeum ''Zospeum'' is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Ellobiidae, the salt marsh snails. Species Species within the genus ''Zospeum'' include: ** '' Zospeum allegrettii'' Conci, 1956 ** '' ...

'' * Tashan cave snail (''Trogloiranica tashanica'')

Velvet worm Onychophora (from grc, ονυχής, , "claws"; and , , "to carry"), commonly known as velvet worms (due to their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus (after the first described genus, '' Peripatus ...
s

* White cave velvet worm (''Peripatopsis alba'') * ''

Speleoperipatus spelaeus ''Speleoperipatus'' is a monospecific genus of Onychophora, velvet worm in the Peripatidae family, containing the single species ''Speleoperipatus spelaeus''. This species is a pale greenish yellow, almost white, with 22 or 23 pairs of legs and n ...

Arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
a

Arachnid Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroon ...
a

Kauaʻi cave wolf spider The Kauai cave wolf spider (''Adelocosa anops'', the only species in the genus ''Adelocosa''), also known to local residents as the blind spider, is only known to occur in a few caves in a lava flow with an area of in the Kōloa– Poipū regi ...

(''Adelocosa anops'') * Nelson cave spider (''Spelungula cavernicola'') *'' Calicina cloughensis'' *''

Texella reddelli ''Texella reddelli'', the Bee Creek cave harvestman, is a rare species of troglobitic harvestman that was added to the United States endangered species list in 1988, at the same time as six other species native to the karst ecosystem in Travis ...

'' *'' Trogloraptor marchingtoni'' *'' Apochthonius mysterius'' – Mystery Cave pseudoscorpion *'' Apochthonius typhlus'' – Stone County cave pseudoscorpion *'' Hesperochernes occidentalis'' – guano pseudoscorpion *'' Mundochthonius cavernicolus'' – cavernicolous pseudoscorpion *'' Phanetta subterranea'' – cave spider *''

Porrhomma cavernicola ''Porrhomma'' is a genus of sheet weavers that was first described by Eugène Louis Simon in 1884. Species it contains twenty-five species, found in Europe and Asia: *'' Porrhomma altaica'' Růžička, 2018 – Altai (Russia, Kazakhstan) *'' P ...

'' – cavernicolous ''Porrhomma'' spider *'' Porrhomma rosenhaueri'' – A blind cave Spider (very rare) *'' Sinopoda scurion'' – eyeless huntsman spider *'' Troglokhammouanus steineri'' – Xe Bang Fai cave scorpion *'' Vietbocap lao'' – Nam Lot cave scorpion *'' Parobisium yosemite'' – Yosemite cave pseudoscorpion *'' Titanobochica magna'' – cave pseudoscorpion *'' Cicurina madla'' – Madla Cave meshweaver *'' Chinquipellobunus madlae'' – cave harvestman *''

Stalita taenaria ''Stalita taenaria'' is an Araneomorphae, araneomorph spider species in the family Dysderidae. The species is classified as a member of troglofauna, more precisely a troglobiont species, meaning such spiders are obligate cave-dwellers adapted to ...

'' *'' Mesostalita nocturna'' *''

Chthonius In Greek mythology, the name Chthonius or Chthonios (, , "of the earth or underworld") may refer to: *Chthonius, an Egyptian prince as one of the sons of King Aegyptus.Apollodorus, 2.1.5 His mother was the naiad Caliadne and thus full brother o ...

'' *'' Neobisium maritimum'' *''

Agraecina cristiani ''Agraecina'' is a genus of liocranid sac spiders that was first described by Eugène Louis Simon in 1932. Species it contains six species, found in Africa, Europe, Spain, and Kazakhstan: *''Agraecina canariensis'' Wunderlich, 1992 – Canary ...

'' - Movile Cave spider

Myriapoda Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. The fossil record of myriapods reaches back into the late Silurian, a ...

;Millipedes Sinocallipus deharvengi head

*'' Causeyella'' species *'' Chaetaspis aleyorum'' – Aleys' cave millipede *'' Chersoiulus sphinx'' *''

Desmoxytes ''Desmoxytes'', whose species are commonly known as the dragon millipedes, is a genus of millipedes of the family Paradoxosomatidae found in Southeast Asia. The genus was described by Ralph Vary Chamberlin in 1923, and reviewed by Sergei Golovat ...

'' *'' Mammamia profuga'' *'' Polydesmus subterraneus'' *'' Sinocallipus'' *'' Titanophyllum spiliarum'' *''

Trichopetalum whitei ''Trichopetalum whitei'', common name Luray Caverns blind cave millipede, is a rare troglobitic (obligate cavernicolous) millipede of the upper Potomac River drainage in four Virginia counties and three West Virginia counties. It has been record ...

'' *'' Tingupa pallida'' *'' Zosteractis interminata'' ;Centipedes *''

Eupolybothrus cavernicolus ''Eupolybothrus cavernicolus'' is a species of centipede so far only found in two caves near the village of Kistanje, in Šibenik-Knin County, Croatia. It has been dubbed the ''cyber-centipede'' as it is the first eukaryotic species for which, i ...

'' *'' Scolopocryptops troglocaudatus''

Crustacea Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...

;

Crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

;Others *'' Allocrangonyx hubrichti'' – Hubricht's long-tailed amphipod *'' Andhracoides shabuddin''– Guthikonda cave isopod *'' Andhracoides gebaueri''– Belum cave isopod *''

Androniscus dentiger ''Androniscus dentiger'', the rosy woodlouse or pink woodlouse is a species of woodlouse found from the British Isles to North Africa. Description ''A. dentiger'' is a small woodlouse, at only 6 mm (¼ in) long, and is characteristica ...

'' – rosy woodlouse *''

Alpioniscus strasseri ''Alpioniscus'' is a southern European genus of woodlouse, woodlice in the family Trichoniscidae. Alpioniscus consists of two subgenera: ''Alpioniscus s.s.'' and ''Illyrionethes''. A 2019 study used molecular and taxonomic analyses to verify the ...

'' *'' Bactrurus brachycaudus'' – short-tailed groundwater amphipod *'' Bactrurus hubrichti'' – sword-tail cave amphipod *'' Bactrurus pseudomucronatus'' – false sword-tailed cave amphipod *'' Barburia yanezi'' *'' Caecidotea antricola'' – cave isopod *'' Caecidotea dimorpha'' –

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

cave isopod *'' Caecidotea fustis'' – Fustis cave isopod *'' Caecidotea salemensis'' – Salem cave isopod *'' Caecidotea serrata'' – serrated cave isopod *'' Caecidotea stiladactyla'' – slender-fingered cave isopod *'' Caecidotea stygia'' – stygian cave isopod *''

Cancrocaeca ''Cancrocaeca xenomorpha'' is a species of troglobitic (cave-dwelling) freshwater crab from Sulawesi, the only species in the monotypic genus ''Cancrocaeca''. It has been described as the world's "most highly cave-adapted species of crab". Desc ...

'' *''

Cyclops vernalis In Greek mythology and later Roman mythology, the Cyclopes ( ; el, Κύκλωπες, ''Kýklōpes'', "Circle-eyes" or "Round-eyes"; singular Cyclops ; , ''Kýklōps'') are giant one-eyed creatures. Three groups of Cyclopes can be distinguish ...

'' *'' Diacyclops yeatmani'' – Yeatman's groundwater copepod *'' Gammarus acherondytes'' –

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

cave amphipod *'' Holoped amazonicum'' *'' Lirceus usdagalun'' – Lee County cave isopod *'' Macromaxillocaris'' *''

Niphargus ''Niphargus'' is by far the largest genus of its family, the Niphargidae, and the largest of all freshwater amphipod genera. Usually, these animals inhabit caves or groundwater. They occur in western Eurasia, in regions that were not covered by ...

'' species *'' Orcovita hickski'' *'' Orcovita orchardorum'' *''Palaemonias alabamae'' - Alabama cave shrimp *'' Samarplax principe'' *''

Spelaeorchestia koloana ''Spelaeorchestia koloana'', the Kauai cave amphipod or ' in Hawaiian, is a cave-dwelling crustacean only found on the Hawaiian island of Kauai. It is eyeless and measures long. It is only known from 10 populations, and eats decaying plant ma ...

'' *'' Stygobromus barri'' – Barr's groundwater amphipod *'' Stygobromus clantoni'' – Clanton's groundwater amphipod *'' Stygobromus heteropodus'' – Pickle Springs amphipod *'' Stygobromus onondagaensis'' – Onondaga cave amphipod *''

Stygobromus ozarkensis ''Stygobromus'' is a genus of Amphipoda, amphipod crustaceans that live in subterranean habitats. As well as a large number of species in North America, a smaller number of species are also known from Eurasia. Most of the North American species l ...

'' – Ozark cave amphipod *'' Stygobromus putedus'' – Wisconsin groundwater amphipod *'' Stygobromus subtilis'' – subtle groundwater amphipod *''

Typhlocaris ''Typhlocaris'' is a genus of blind troglobite, cave-dwelling Caridea, shrimp, placed in its own family, Typhlocarididae. It contains 4 species: *''Typhlocaris ayyaloni'' Tsurnamal, 2008 – Israel *''Typhlocaris galilea'' Calman, 1909 – Isra ...

Insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
a

''See

Cave insects Cave-dwelling insects are among the most widespread and prominent troglofauna (cave-dwelling animals), including troglobites, troglophiles, and trogloxenes. As a category of ecological adaptations, such insects are significant in many senses, ecolo ...

Fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

* List of cave fish

Amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
s

Cave salamander A cave salamander is a type of salamander that primarily or exclusively inhabits caves, a group that includes several species. Some of these animals have developed special, even extreme, adaptations to their subterranean environments. Some speci ...

Mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s

There are no known mammals that live exclusively in caves. Most

s sleep in caves during the day and hunt at night, but they are considered

troglophile Troglofauna are small cave-dwelling animals that have adapted to their dark surroundings. Troglofauna and stygofauna are the two types of subterranean fauna (based on life-history). Both are associated with subterranean environments – troglofau ...

s or

s. However some

fossorial A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees. Prehistoric eviden ...

s which spend their whole lives underground might be considered subterranean

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...

, although they are not true troglofauna as they do not live in caves.

References

{{Reflist, 24em Cave animals

Troglobites 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 u ...

Flatworm The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegment ...s

Mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

Velvet worm Onychophora (from grc, ονυχής, , "claws"; and , , "to carry"), commonly known as velvet worms (due to their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus (after the first described genus, '' Peripatus ...s

Arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...a

Arachnid Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroon ...a