Troglomorphism is the morphological adaptation of an animal to living in the constant darkness of caves, characterised by features such as loss of pigment, reduced eyesight or blindness, and frequently with attenuated bodies and/or appendages. The terms
troglobitic, stygobitic,
stygofauna,
troglofauna, and
hypogean or hypogeic, are often used for cave-dwelling organisms.