The Human Fish Proteus anguinus

Features

The Human Fish is a rare amphibian and the only vertebrate that lives in the water of the underground karst.

Species	Amphibian
Living space	Groundwater
Size	20 to 30 cm
Weight	17 grams

Description

The Human Fish is the largest cave animal in the world and the only cave vertebrate in Europe. They are typical cave animals lacking both dark skin color and eyes. In the larvae, the eyes are still visible, and are later stunted and grown over by skin. Their entire bodies are sensitive to light (dermatoptic sense) and the Human Fish also has well-developed senses of smell and taste, a specially developed inner ear, and a peculiarity – their sense organs that can detect electric fields. They also have two pairs of weak legs that stand far apart, with three toes on each of the front legs and two toes on each of their hind legs, which are solely auxiliary in terms of movement. They breathe using their outer gills which, thanks to the blood that is visible through their skin, are vivid red in color. They also have simple lungs. There is little visible difference between the male and female externally. The Human Fish prefers underground water systems in the Karst environment with calm, well-ventilated waters and a stable low water temperature. The Human Fish was first found and described in the Slovenian karst, and the majority of research has been carried out on animals found on Slovenian soil.