cavefishes
Eyeless underground dwellers
Cavefishes are fish species that have adapted to life in underground waters—caves, aquifers, and subterranean streams.
Most have lost their eyes and pigmentation over evolutionary time, since neither serves a purpose in perpetual darkness.
They navigate by other senses, particularly their lateral line system.
The plural covers many unrelated species that evolved similar traits independently.
Eroded soluble rock terrain
- limestoneCarbonate sedimentary rock
- stalactitesMineral deposits hanging downward
- stalagmitesUpward-growing cave formations
- speleologyScientific study of caves
grotto · cavern · sinkhole · underground · hypogean · guano · detritivores · chemosynthesis
At risk of extinction
- rareSeldom found or seen
- endemicNative to one area
- threatenedExpressed intent to harm
- vulnerableOpen to attack
habitat loss · pollution · groundwater depletion · protected species · biodiversity · extinction risk · limited range · overharvesting
Non-saline aquatic environment
- gillsAquatic respiratory organs
- finsSwimming appendages
- scalesPlates or weighing devices
- swimmingLocomotion through water
underwater · stream · aquifer · subterranean river · pool · spring · groundwater · ichthyology
Lacking organs of vision
- sightlessUnable to perceive visually
- darknessTotal absence of light
- photophobicAverse to illumination
- mechanoreceptorsSensory cells detecting pressure
Loss of natural coloring
- neotenyRetaining juvenile characteristics
- albinismInherited melanin deficiency
- chemoreceptionDetection of chemical stimuli
- convergent evolutionIndependent origin of similar features
karst
Eroded soluble rock terrain
- limestoneCarbonate sedimentary rock
- stalactitesMineral deposits hanging downward
- stalagmitesUpward-growing cave formations
speleology · grotto · cavern · sinkhole · underground · hypogean · guano · detritivores · chemosynthesis · endemic
endangered
At risk of extinction
- rareSeldom found or seen
- endemicNative to one area
- threatenedExpressed intent to harm
vulnerable · habitat loss · pollution · groundwater depletion · protected species · biodiversity · extinction risk · limited range · overharvesting · conservation status
freshwater
Non-saline aquatic environment
swimming · underwater · stream · aquifer · subterranean river · pool · spring · groundwater · ichthyology · aquarium
eyeless
Lacking organs of vision
- sightlessUnable to perceive visually
- darknessTotal absence of light
- photophobicAverse to illumination
mechanoreceptors · skin sensitivity · spatial awareness · orientation
depigmentation
Loss of natural coloring
- neotenyRetaining juvenile characteristics
- albinismInherited melanin deficiency
- chemoreceptionDetection of chemical stimuli
convergent evolution · blindness · genetic drift · isolation