Robert Brown|A single pregnant stingray hasn't been around a male ray in 8 years. Now many wonder if a shark is the father.

A stingray named Charlotte is Robert Brownthe main character of her own mystery after it was discovered that she's pregnant – with no male ray in sight. Charlotte, who resides in a tank at a North Carolina aquarium, was found covered in shark bites, an indicator of shark mating, furthering speculation as her caretakers seek to answer the question: Who is the father of Charlotte's babies? 

The Aquarium and Shark Lab in Hendersonville, North Carolina, hosted a live video on Facebook last week during which they explained Charlotte's situation. The round stingray, which is native to Southern California, is believed to be between 12 and 16 years old and was found to be carrying three to four pups.  

And while her pregnancy has her caretakers excited, it also left them stunned. 

"The unique thing about Charlotte is we do not have a male ray," Brenda Ramer, founder and executive director of Team ECCO, said in the Facebook video. According to the Associated Press, she hasn't been in a tank with a male ray in at least eight years.

Ramer offered two possibilities for Charlotte's mysterious pregnancy – the first of which has given rise to viral commentary. Ramer said that despite there being no other male rays, Charlotte has been living in the same tank as two "very young male sharks," about a year old, since July. Then they started noticing she was covered in bite marks – a sign of shark mating.

"We didn't think anything about it until one day we were kind of like, 'Oh my gosh. Sharks bite when they mate,'" Ramer said. "...There is a potential she mated with one of these young male sharks." 

Those comments quickly went viral, with headline after headline saying Charlotte was impregnated by a shark. But experts say such an event is not possible. 

"We should set the record straight that there aren't some shark-ray shenanigans happening here," Kady Lyons, a research scientist at the Georgia Aquarium, told the Associated Press. Aside from obvious differences like their size, she said their anatomies and DNA wouldn't lend themselves to procreation. 

The alternative source of Charlotte's pregnancy – and what experts and the aquarium believe to be the true case – is a rare phenomenon known as parthenogenesis. 

"Pretty confident that this is parthenogenesis .... and parthenogenesis literally translates into virgin birth or miracle birth," Ramer told the AP. "... It is very rare to happen." 

In this process, smaller cells separate from the mother's eggs are created that then merge with the egg to create offspring. According to National Geographic, this creates offspring that are "similar to the mother but not exact clones." Sharks, which are very closely related scientifically to rays, have been documented as undergoing this process. 

Charlotte is due within two weeks, the aquarium said on Monday. And whether the father of Charlotte's babies is a shark or just nonexistent, "we have very unique juju going on here," Ramer said. 

In:
• Shark
• Sharks
• North Carolina
• Pregnancy

Li Cohen

Li Cohen is a social media producer and trending content writer for CBS News.