The bizarre “baby dragon” amphibians have been found at a record depth in a secluded underground lake in Croatia. The creatures, known officially as olms (Proteus anguinus), were discovered by extreme cave divers at depths 113 meters (370 feet) below the surface inside a dark limestone cave.
This is the deepest these amphibians, which are native to the Balkans and Italy, have ever been found. Spending their entire lives in perpetual darkness, the creatures are well adapted to live at these depths with zero sunlight. While this is the deepest researchers have found them so far, they expect that they live even deeper. However, the limits of humans diving in such extreme conditions mean we don’t yet know precisely how deep they go.
Olms are truly weird little creatures, and it is this oddity that has endeared biologists to the peculiar amphibian. With a long snake-like body and stumpy legs, they can reach up to 0.3 meters (1 foot) in length, making them one of the largest creatures to call the caves under the Dinaric Alps home. They are the only exclusively cave-dwelling chordate – or animal with a backbone – in all of Europe, and one of the few species of totally aquatic amphibians.
Having lost the pigment in their skin due to their subterranean lifestyle, they are sometimes referred to as “human fish” due to the similarity in their pinkish flesh to that of humans. But they are more frequently known as “baby dragons”, as their elusive speleological behavior flared the imagination of locals, who used to believe that the amphibians were the young of dragons when they occasionally washed to the surface.
With a range restricted to the caves of Slovenia, Italy, Croatia, Bosnia, and Herzegovina, not much is known about the critters due their highly secretive life and extremely challenging environment. The race is on by both conservationists and biologists to learn as much as they can about them, as the limestone karst caves and lakes in which they live are being threatened.
The waters that flow though the caves are becoming more and more polluted, putting the future of the amphibians at risk. Researchers are trying to use new technology, such as identifying trace DNA of the animals from surface streams, to try and pinpoint new populations of olms in remote cave systems, while others are trying to understand how they reproduce in order to develop a captive breeding population.
[H/T: New Scientist]
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