Slovenian Cases

Human Fish (Proteus anguinus)

an example of scientific and educational tourism, well integrated into the general tourist offer of the area, which has positive impacts on preservation of human fish;

Key words:
scientific and educational tourism

The habitat of Proteus anguinus (“human fish”) is very limited. It lives in the subterranean fresh waters of the Dinaric Alps, along the Adriatic Sea, from Venetia to Herzegovina (Istria, Slovenia, Dalmatia, Croatia). It prefers underground water systems in Karst formations, with calm, well oxygenated water and a constant low water temperature. Proteus anguinus was first discovered and described in Slovenian Karst, and most researches were made on animals found in the Slovenian territory as well.

Photo: Slavko Polak

Proteus anguinus is completely adapted to eternal subterranean darkness as it hides in the depths of underground caves for its whole life. Therefore, the pale skin contains no protective pigment and it is whitish with a pink hue due to the skin capillaries (similar colour to that of Caucasian human beings—hence the creature’s name). The tiny eyes can be seen only at the foetal stage, later they are grown over with skin. The head is elongated with a rounded snout. The front legs bear 3, the rear legs 2 toes. The flattened tail used for swimming is markedly shorter than the body. The animal stays in water its entire life and breathes with gills, even though it has rudimentary lungs. Proteus anguinus is approximately 25-30cm long, which makes it the biggest cave animal in the world. At the same time, it is also the only cave adapted vertebrate in Europe.
Proteus anguinus parkelj (“black human fish”) has well developed eyes and pigment, which gives it black color due to regular sun exposure as it often comes from the underground for food. It is found only in Bela Krajina, south east Slovenia

During 19th and in the beginning of 20th century the human fish instantly won the sympathies of the entire scientific world and, it seems, everybody wanted to see and study this rare creature. Consequently, the trade with animals grown into profitable "business".
The survival of Proteus anguinus also depends on large aquatic cave systems and the conservation of sylvan and pastoral land above. Tourism, economic changes and industrial pollution are the main threats to this endangered species. The decline of the known populations in Gorizia (Italy) and Postojna (Slovenia) is well established. Possible reasons for the decline are: general habitat alteration and loss; local and long-distance pesticides, fertilisers, toxins, and other pollutants; intentional mortality due to over-harvesting pet trade or collecting.


Apart from its unique cave morphology, the image and the recognition of the Postojna cave is, in the big part, build on “human fish”. Even more, Postojna Cave is the cradle of speleobiology, the branch of biological science, which studies the living world underground. It was in Postojna Cave that the first specimens of most groups of cave fauna were found. In terms of variety and number of species of cave fauna, the Postojna-Planina cave system is the richest cave system in the world.

Photo: Arne Hodalic

In the 1922, Slovenia protected Proteus anguinus and all cave animals, while in 1982 Proteus anguinus was put on the list of rare and endangered wild animals, which prohibits their trade. Very early on, the possibilities of scientific and educational tourism were recognised. Therefore, the tourist offer of Postojna cave also includes the Proteus Postojna Speleobiological station, a museum that features Proteus along with other invertebrate cave fauna. New Proteus complex offers multimedia presentation of the Karst and life in the underworld, a presentation of the morphology (form and history) of the cave, and a vivarium containing live specimens of cave fauna from Postojna Cave. Special attention is paid to the "human fish". The cave also features a speleobiological laboratory.  

Further information

Scientific and educational tourism can best be included in the general tourist offer, at the same time, it also serves as a protection tool for some rare and endangered species.


Can tourism further scientific research and protection of endangered species?


Prepared by:
IIDE – Institute for Integral Development and Environment (Marta Vahtar, Maja Zdesar and Miran Rusjan)