It looks like the little ‘dragons’ are growing
We have ventured into the olm’s waters - completely without any lights or disruptive external elements in the aquarium. We photographed the olm in its dark environment without additional illumination. What we captured was not the darkness, but what we had waited and hoped for all along – the olms’ embyonic development with visible cell division. To put it simply: it looks like the little ‘dragons’ are growing."
This was, during their visit to the cave, further confirmed by two experts on the biology of olms, Dr. Lilijana Bizjak Mali from the Biotechnical Faculty in Ljubljana, and Dr. Stanley Sessions, a molecular biologist and expert on integrative biology of amphibians from Hartwick College, New York, USA.
The interest shown in the olm and her eggs has been extraordinary, quite surprisingly so. People from all over Slovenia are asking about the situation in the aquarium on a daily basis and Postojna Cave visitors are enthusiastically watching live coverage from the aquarium and, understandably, wondering when ‘the little dragons’ will be here and how many of them there will be.
The answer to the question about how many of the current 55 olm eggs will develop into young olms is unknown and could not be predicted even by the two distinguished visitors. In fact, the eggs are at present only in the first stage of development, which is in olms much longer than in other chordate species, i.e. up to two weeks. The first stage will be followed by two more, with the development additionally affected by the water temperature. At a water temperature of 11 °C, the process lasts for at least 120 days; in our aquarium, the water is somewhat colder (9 °C), as a result of which the entire process will certainly take even longer. The dragons will keep us waiting for a while.
Unfortunately, an interest in eggs has not been shown only by the day visitors to the cave, but also by other cave inhabitants – cave amphipods, small crustaceans, which see olm eggs as one of the most special treats, so they persistently try getting hold of them. This has brought out the olm’s incredible, almost supernatural abilities and a moving maternal instinct. Despite her lack of vision, the olm has (so far) successfully scared away all of the subterranean intruders. We are keeping our fingers crossed for the "Dragon Mom" to make it.
Photo: Iztok Medja for Postojnska jama