This sketch of the olm appeared in an Austrian text published in 1768 by Josephus Nicolaus Laurenti, who game the animal its scientific name.

The olm is like a cross between Peter Pan and Gollum. It never grows up, retaining the red, feathery gills of its larval form even when it becomes sexually mature at sweet sixteen. It stays this way for the rest of its remarkably long life, and it can live past 100. Photo by Arne Hodalič

The olm is an iconic animal in Slovenia, and its presence provides a boost to local ecotourism. One of the caves where it lives does tours around the research station. And as you can see, the olm features on a Slovenian coin. 

The olm is a blind, cave-dwelling salamander, also called the proteus and the “human fish”, for its pale, pinkish skin. It lives in caves in Eastern Europe. Photo by Arne Hodalič

The olm is almost entirely blind. It has no need for eyes in the darkness of its caves and as it grows up, they stop developing and are eventually covered by layers of skin. Nonetheless, the hidden eyes and even parts of its skin can still detect the presence of light. The olm also has an array of supersenses, including heightened smell and hearing and possibly even the ability to sense electric and magnetic fields. Photo by Arne Hodalič