CROATIAN FAUNA 2013 - AMPHIBIANS - OLM (PROTEUS)

OLM (PROTEUS)
 
Despite of its name (Croatian name for olm is human fish) olm or Proteus anguinus (Laurenti 1768) does not belong to the class of fishes but to amphibians. The adjective human standing before the substantive fish suggests the colour of skin of this species which is pinkish like human skin. It inhabits only fresh water of the karst underground of Dinaric Mountains and is an endemic species of Dinaric karst. Due to its peculiar look it was believed in history to be a kite’s baby. Though a real underground amphibian, it can also be found on earth’s surface, when brought by an underground torrent. It is well adapted to specific underground world. Its eyes are undeveloped (rudimentary) and covered with skin layer while its other sensors are very well developed. With its chemo receptors it can detect small quantities of food, its very sensitive hearing is further strengthened by a side line sensitive to vibrations; it also possesses an ambulatory organ by which it can sense electric field. It feeds on insects’ larvae, snails and small crabs. It is a very interesting fact that this animal, so well adapted to the underground world, when exposed to outside conditions can get darker skin and can develop the sense of sight.
 Olm is unique in many aspects. It is an amphibian with the longest lifespan − it can live up to 100 years. It stays forever young-looking since it preserves the look of larvae during its whole life. This phenomenon is called neoteny and can be seen in olm on its outer gills. It is the only European amphibian adapted to life underground. About 30 centimetres long, it is the biggest cave animal in the world. In the Republic of Croatia it is strictly protected and globally it is considered an endangered species.

Anđela ćukušić