A Female Stingray That Hasn't Had a Mate in Eight Years Is Mysteriously Pregnant. Is a Shark the Father?
Though the round stingray, named Charlotte, shares her aquarium tank with two male sharks, experts say it is impossible for a shark to impregnate a ray
02/16/2024
A female stingray has become the topic of international attention after getting pregnant under unprecedented circumstances. The rust-colored round stingray, named Charlotte, swims in a storefront aquarium in Hendersonville, North Carolina. And in a phenomenon baffling aquarium staff, Charlotte is due to have up to four pups—but she hasn’t encountered a male mate in at least eight years.
“It’s a once in a bluest of blue moons experience,” says Brenda Ramer, executive director of the Aquarium and Shark Lab by Team ECCO, where Charlotte lives, to ABC News 13’s Brittany Whitehead and Justin Berger.
Charlotte, believed to be between 12 and 16 years old, was found to have mysterious growths swelling on her body, which Ramer initially thought might indicate cancer. But when staff ran an ultrasound on the ray, they discovered something even more startling: eggs.
“I reached out to Dr. Rob Jones, the aquarium vet, and he identified the growth as eggs,” Ramer tells ABC News 13. And that raised questions. “We have no male ray.”
Though Charlotte had not shared a tank with a male stingray in years, she has inhabited the same space as two male white-spotted bamboo sharks, named Larry and Moe, since July 2023. Ramer recently noticed bite marks on Charlotte, a sign of shark mating. This led her to two possible explanations for the pregnancy: Charlotte reproduced asexually, or she was impregnated by one of the sharks in her tank. Either option would be a scientific first.
However, other experts have thrown cold water on the shark theory. Kady Lyons, a research scientist at the Georgia Aquarium in Atlanta, tells Ben Finley of the Associated Press (AP) it’s impossible Charlotte was impregnated by a shark: the two species’ anatomies are not compatible and neither is their DNA.
“We should set the record straight that there aren’t some shark-ray shenanigans happening here,” says Lyons to the AP.
Rather, the ray’s pregnancy may be better explained by a process called parthenogenesis, a phrase with Greek roots that translates literally to “virgin creation.” Parthenogenesis is a rare form of asexual reproduction in which a female produces an embryo without fertilization by a male’s sperm. Instead, a smaller cell known as a “polar body,” which forms at the same time as the egg and contains DNA similar to the mother’s, merges with the fertile egg. This creates offspring that are “similar to the mother but not exact clones,” wrote National Geographic’s Corryn Wetzel in 2020.
Parthenogenesis has been observed in more than 80 vertebrate species, including California condors and a crocodile.
“We know that many species of sharks and rays are capable of parthenogenesis,” says Chris Lowe, director of the shark lab at California State University, Long Beach, to Forbes’ Conor Murray. “This is a very interesting phenomenon and quite cool considering it occurs across so many species of sharks and rays, but we don’t really know why this is so common across this group of animals and not others.”
Though parthenogenesis has been seen before, Charlotte’s specific species, the round stingray, has never been reported to give birth this way. Still, experts say the theory provides a much more plausible explanation than impregnation by a shark does. Since it’s difficult to identify how often parthenogenesis occurs in the wild, animals in human care are often the ones that reveal a species is capable of asexual reproduction, in so-called unprecedented “firsts,” according to National Geographic.
“I give a shark the same odds of being the father that I would give Elvis or Bigfoot of being the father—zero,” says Demian Chapman, senior scientist and director of the Mote Marine Laboratory and Aquarium’s center for shark research, to Forbes.
Charlotte is expected to give birth within the next two weeks, according to the Associated Press. Ramer plans on moving Charlotte to a much larger tank to accommodate her offspring, equipped with live cameras for spectators to observe the historic and attention-grabbing stingray newborns.
“When the birth happens, we’ll get the babies moved to the tide pool. It’s like our little nursery tank,” says Kinsley Boyette, assistant director of the aquarium, to Hendersonville Times-News’ Dean Hensley. “We’re just hoping for happy and healthy babies.”
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