|Olms in Postojna Cave, Slovenia|
Sket & Arntzen, 1994
The olm or proteus (Proteus anguinus) is an aquatic salamander in the family Proteidae, the only exclusively cave-dwelling chordate species found in Europe. In contrast to most amphibians, it is entirely aquatic; it eats, sleeps, and breeds underwater. Living in caves found in the Dinaric Alps, it is endemic to the waters that flow underground through the extensive limestone bedrock of the karst of Central and Southeastern Europe, specifically southern Slovenia, the basin of the Soča River (Italian: Isonzo) near Trieste, Italy, southwestern Croatia, and Bosnia and Herzegovina. Introduced populations are found near Vicenza, Italy, and Kranj, Slovenia.
It is also called the "human fish" by locals because of its fleshy skin color as well as "cave salamander" or "white salamander". In Slovenia, it is also known by the name močeril.
It was first mentioned in 1689 by the local naturalist Valvasor in his Glory of the Duchy of Carniola, who reported that, after heavy rains, the olms were washed up from the underground waters and were believed by local people to be a cave dragon's offspring.
This cave salamander is most notable for its adaptations to a life of complete darkness in its underground habitat.
It has three toes on its forelimbs, but only two toes on its hind feet. It also exhibits neoteny, retaining larval characteristics like external gills into adulthood, like some American amphibians, the axolotl and the mudpuppies (Necturus).
Images for kids
The research vent-hole in Jelševnik near Črnomelj, where quality checks of water and sediments are performed regularly, and where activities of black olms are registered with an IR camera
Olm Facts for Kids. Kiddle Encyclopedia.