Anna the anaconda gave birth to a litter of baby snakes at the New England Aquarium in January—while she was completely isolated from any male snakes. The aquarium’s biologists said the birth had to be an immaculate conception, known as “parthenogenesis” in biology, which loosely translates to “virgin birth” in Greek. DNA testing confirmed that the 2-foot-long, green anaconda babies are the product of nonsexual reproduction. Parthenogenesis is an extremely rare reproductive strategy among vertebrate species, and Anna’s is only the second known confirmed case in a green anaconda.

“Genetically, it’s a vulnerable process,” aquarium spokesman Tony LaCasse said. “It’s among that tagline, ‘life will find a way.’ It’s a completely unique and amazing reproductive strategy, but it has a low viability compared to sexual reproduction.” The aquarium’s resident biologist found three live babies and about a dozen stillborn, a common occurrence with parthenogenesis births. The young snakes are genetic copies, or clones, of the mother.