Caves, castles, and cousins in Slovenia

Alright, where to next? I just mentioned how our last destination, Croatia, was a lesser known country to most North Americans, well the next one we went to is likely one of the least known countries in all Europe, Slovenia. Family ties brought my sister and myself here as my mother was born and raised in Maribor and Koper, Slovenia.

With quality family time with our generous distant cousins we took a trip from Maribor to Bled (gorgeous castle on a cliff and church on the lake) to the coastal towns of Koper and nearby Salt Flats of Sečovlje. And finally, our last stop was Postojna to visit the Predjama Castle a 16th century medieval castle build on a cliff in the mouth of a cave, one of many castles in Slovenia) and the spectacular underground Postojnska Cave systems.

You can check out my sister’s video Castle on a Cloud of our travels around Slovenia. Of course, being a geologist and “rock-nerd” I am going to have to focus on the caves here for this blog post and enlighten there incredible formation for you, as well as a rather unique resident of the caves…

Cave formation and human fish

Exploring the caves via train and walking through the winding passages is a surreal experience. With over 21 kilometers of winding passages you can’t even begin to grasp the actual size of these cave systems.

The reason for such extensive tunneling again relates to the rocks. The rock type is vastly limestone, with lesser dolostone. The cave formed over 2 million years ago by an underground river (called Pivka) carving its way through the soft surrounding limestone bedrock. Not until about 100,000 years ago did the eye-catching pillars of stalactites (top-down) and stalagmites (bottom-up) form. This was through the extremely slow (between 0.1-0.3 mm/year) process of water percolating down from the ceiling and depositing calcite that was dissolved within the H₂O.

Finally, I cannot end this post without mentioning the human fish! So a little biology (and ecology I guess?) for you. The Proteus or ‘human fish’ is one of the largest cave-dwelling animals, and is an amphibian in the same order (Caudata) of salamanders and newts. It is a living, text-book example of adaptation of a species to it environment overtime (+1 for Darwin). With atrophied eyes, no dark protective skin pigments, and a highly developed sense of smell, tough, taste, and hearing (it can even detect weak electrical fields, like bats!) it has become completely immersed and consummated with its dark and damp cave environment, so well that it can even survive several years without food and live up to a hundred years!

Final thoughts

As one of the greenest countries in Europe, Slovenia has a deep sense of natural beauty. I loved my family time in this lesser known and lesser touched country. Filled with friendly locals and enduring culture, Slovenia holds boundless surprises!

-Stephanie

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