Tourists watch rare sight of olm eggs hatch in Postojna Cave (2)

An olm with its eggs are seen in Postojna Cave, Slovenia, March 15, 2016. Olms are very sensitive to stress, which is why visitors entering the part of the cave where the olms can be seen in an aquarium are asked to keep quiet and not take any photos. In order not to disturb the olm or Proteus anguinus protecting its eggs, biologists covered the aquarium with black covers until the eggs hatch. This blind cave salamander was seen to lay eggs in its natural habitat of a cave only once before, in the same cave in 2013, but all were lost because of a stressful event. In late January 2016 the exceptional event occured again when an olm layed 57 eggs. Biologists covered its water tank to keep it in darkness, and set up an infrared camera that broadcasts a live video stream to a monitor where visitors can see what is happening. The cave's staff and scientists can also access the same live video stream on their laptops anywhere over a wifi connection. It will now take 120 days in 11 degrees Celsius water for the eggs to hatch, but given the high mortality rate of olm eggs, biologists estimate that only three eggs would hatch in June this year. If or when they do, it will be the first time ever anywhere in the world for scientists to witness olm eggs hatch in the animal's natural environment of the cave. (Xinhua/Luka Dakskobler)