When humans in the 15th century encountered olms—rare amphibians that have been roaming Earth's caves for 200 million years—they thought they were baby dragons. Today we know little more about the blind creatures than our ancestors did. Olms inhabit the cave rivers of the Balkans, grow up to a foot long, can live for a century, and only need to eat once a decade, report the BBC and Slate. They also lay eggs about as often, which is why the 50 to 60 olm eggs stuck to the underside of a rock in Slovenia's Postojna Cave are so remarkable. The cave hosts a wild olm population alongside an aquarium visited by a million tourists each year. On Jan. 30, a female olm chose an area in the aquarium to lay her eggs, three of which are showing promising signs of growth, biologist Saso Weldt says. It will likely take at least four months for the eggs to hatch.
"It is very significant because there is not a lot of data about anything [relating to] the reproduction of this group of animals," says a researcher, adding it would be "something amazing" if any olms hatched and developed. An olm—which the New York Times describes as having a "long sinuous body, stubby legs, and frilly gills"—laid eggs in Postojna Cave in 2013, but all were eaten by other olms or never hatched. This time researchers are allowing only the mother olm access to the eggs, which she monitors with her sense of smell; any that aren't fertilized become food. Scientists are also protecting them from light and are adding extra oxygen to the area because they're vulnerable to changes in water quality and temperature. "Now it's up to them," says Weldt. "We are hoping that in a couple of months we can state that we have baby dragons." (This is the world's largest amphibian.)