Subterranean fauna refers to animal species that are adapted to live in an underground environment. Troglofauna and stygofauna are the two types of subterranean fauna. Both are associated with hypogea
The olm (Proteus anguinus), a typical cave dwelling chordate, endemic of Dinaric Alps
The microscopic cave snail Zospeum tholussum, found at depths of 743 to 1,392 m (2,438 to 4,567 ft) in the Lukina Jama–Trojama cave system of Croatia, is completely blind with a translucent shell