The Human Fish has the scientific name of Proteus anguinus and is also known as the Olm. It has human-looking skin but otherwise there is no resemblance. Nor do they resemble a fish.
Looking similar to a salamander, the P. anguinus is actually a different species. It has many of the adaptations to cave life such as a lack of functioning eyes and pigmentation. It also has a very elongated head.
Although it’s completely blind, the regressed eyes still have some sensitivity to light and even it’s skin is light sensitive. It’s possible this helps it to stay in the darker areas of a cave and away from predators.
P. anguinus is found along the Adriatic Coast in Central and Southeastern Europe, in around 200 caves. It lives entirely in the water and may grow up to 16 inches long.
They live a long time and don’t even reach sexual maturity until they are 16 years old. They can live up to 58 years in the wild and up to 70 years in captivity. These are human-like characteristics that may have contributed to the name.
Although they lack working eyes, P. anguinus has many sensory organs. They have a heightened sense of smell and taste to detect food. They also seem to be able to hear sound waves somewhat. Most amazing is the ability to detect electrical and magnetic fields, possibly for navigation.
They feed on small snails, crabs and insects. Although they have tiny teeth, they actually swallow their food whole. Adapted to the unpredictable food supply in caves, they can actually live for up to 10 years without food.
The Human Fish breathes through red gills located on the outside of the head.
Photo courtesy of Arne Hodalič/CC-BY-SA-3.0
Despite the name being a little misleading, these are fascinating cave animals that would be wonderful to see in their natural environment if you ever get the chance.