“This animal has lost its sexuality,” said study co-author Olivier Jaillon of Genoscope, part of the Institut de Génomique du CEA in France.

Jaillon said the results of the study gave him one of the very rare moments in a career when you feel you’ve really “found something.”

Reproductive Mystery

Bdelloid rotifers are microscopic, multicellular animals that look and move a lot like leeches (“bdelloid” is from the Greek for “leech”). They generally live in freshwater, moist soil, and other damp environments. And these unassuming animals have some pretty cool superpowers: They can withstand long periods of being dried out, as well as massive doses of radiation that would kill pretty much every other living thing.

Despite these traits, bdelloid rotifers are mainly known in the research world for their 40-million-year-long dry spell in the sack. Although biologists long suspected that these microscopic animals never reproduced sexually—they generally reproduce via an asexual method known as parthenogenesis, in which the offspring is the clone of the parent—the assertion remained controversial for several reasons.