Even in an age of viral news stories, Charlotte the stingray is an unlikely celebrity. Like many celebrity news stories, Charlotte has made headlines due to her pregnancy. She is due to give birth in the next week or so, yet the identity of her babies’ father is a mystery.
When the story first broke, many news outlets seemed to suggest there was a chance that Charlotte had been impregnated by one of the small male sharks that she shares a tank with at the Aquarium and Shark Lab by Team ECCO in Hendersonville, North Carolina. After all, there hasn’t been another male stingray in the tank in around eight years. Biologists quickly poured cold water on the shark theory, pointing out that stingrays and sharks are incompatible for mating, both in an anatomical and a genetic sense. The “interspecies mating” theory probably stemmed from a humorous comment made by the aquarium’s owner and executive director, Brenda Ramer.
The real explanation is almost certainly less scandalous yet still fascinating. Charlotte appears to have undergone parthenogenesis, a form of asexual reproduction that does not require any type of mating. Instead, each of her eggs fused with special cells known as polar bodies that were created at the same time as the eggs, thus triggering the process of cell division and the creation of an embryo. While the babies, known as pups, will consist entirely of Charlotte’s genetic material, they are not clones.
Although Charlotte is the first known member of her species to experience parthenogenesis, this rare phenomenon has been documented in other rays, as well as numerous other animals, from California condors to Komodo dragons. And while Charlotte’s pregnancy appears to be a first for round stingrays in captivity, there’s no data on how frequently this occurs in the wild.
An extremely surprising pregnancy:
- Ramer and her staff at the aquarium initially feared that Charlotte had a tumor due to the growing protuberance on her back until an ultrasound revealed that she was pregnant with up to four pups. Now, Ramer hopes to get a livestream set up so that people from around the world can observe Charlotte and her offspring. She also hopes to move them to a much larger enclosure.
- Parthenogenesis literally means “virgin creation.” Though impossible in mammals, it has been documented in at least 80 vertebrates, including certain types of fish, birds, reptiles, amphibians, and insects.
- The round stingray gets its name from its shape, which resembles a plate. They are native to the Pacific Ocean, mostly near the coasts of southern California and Mexico. They are a common sight in shallow waters and have a painful sting if you accidentally step on them.
