A fascinating and unique amphibian found primarily in the underwater caves of the Dinaric Alps in Central and Southeastern Europe. This extraordinary creature, also called the “human fish” due to its pale, pinkish skin, is notable for its adaptations to a life of complete darkness. The olm is the only species in the genus Proteus and holds a special place in both scientific research and folklore.

Physically, the olm is an elongated, eel-like amphibian, growing up to 30 cm (12 in) in length. Its body is adapted to its subterranean environment, with a long, slender shape that allows it to navigate through narrow underwater passages. One of the most striking features of the olm is its skin, which lacks pigmentation, making it appear almost translucent. This adaptation is a result of living in total darkness, where pigmentation provides no survival advantage. The olm’s eyes are another significant adaptation; they are vestigial and covered by skin, rendering the creature effectively blind. Instead of relying on vision, the olm has developed highly sensitive sensory organs that can detect minute changes in the water, helping it navigate and find food.

The habitat of the olm is as unique as the animal itself. It resides in the karst cave systems, which are characterized by their limestone bedrock, creating an extensive network of underground rivers and lakes. These caves provide a stable environment with constant temperatures and humidity, which is ideal for the olm. The water in these caves is typically cold, clear, and low in nutrients, making the olm’s adaptations to such conditions all the more remarkable.

Distribution

Country

Population est.

Status

Year

Comments

Bosnia And Herz.

2022

Croatia

2022

Italy

2022

Introduced

Montenegro

2022

Presence Uncertain

Slovenia

2022