Months after mysterious pregnancy, North Carolina stingray remains under close observation

HENDERSONVILLE, N.C. (WTVD) -- The stingray in western North Carolina who got pregnant under mysterious circumstances months ago still has not given birth.

Charlotte the stingray lives at the Aquarium and Shark Lab in Hendersonville. Back in February, aquarium workers determined that Charlotte was pregnant, but said they were shocked because she had never been in contact with a male stingray.

She became a national sensation when scientists explained there were only two ways they could think of that she got pregnant. Both of which were extremely rare.

The first was a true virgin birth known as parthenogenesis. That's when the eggs develop on their own without fertilization and create a clone of their mother.

The second was that Charlotte mated with male sharks that were in her tank. It's unclear whether that's even possible. The evidence that made scientists consider that option was bite marks on Charlotte's body -- which is expected behavior for mating sharks.

Either way, that was February, and the scientists thought Charlotte was weeks away from giving birth. Three months later, Charlotte has still not given birth.

"Staff is taking extra care and time with Charlotte as we continue this scientific process. We appreciate your continued support and excitement as we navigate this unfamiliar area of science and marine biology," the aquarium said in a recent social media post.

One marine biologist is now suggesting Charlotte's pregnancy could be taking longer than normal because of diapause. It's a process where the female puts her embryos on pause; it happens sometimes when the female is feeling particularly stressed.

Another explanation the biologist offered was that Charlotte's embryos died and she re-absorbed them to take advantage of those nutrients.