A bizarre and rare amphibian is guarding a clutch of 50-60 eggs in Postojna Cave, Slovenia, and the biologists are impatiently waiting for babies as three of them are showing signs of growth.

Olms are blind aquatic salamanders that eat, sleep, and breed entirely underwater, and they are found in cave rivers of the Balkans. Nicknamed dragon because of their long, serpentine bodies, olms have a lifespan of more than 100 years and reproduce only once or twice a decade, reports ScienceAlert.

An olm was first seen laying eggs in the Postojna cave in 2013, and she produced 22. The Slovenian times reports that the pregnant female was aggressively protective and attacked any of the other six olms that got too close.

The biologists are not sure how many will hatch or low long it will take. “Right now it looks like three are good candidates,” Saso Weldt, a biologist , told the BBC.”She started laying eggs on 30 January. She is still laying one or two eggs per day, and they need something like 120 days till they hatch.”

The biologists are waiting to see if the pregnant female will lay more eggs.