In the Aquarium and Shark Lab of Team ECCO in North Carolina, there is a mystery in the water: Charlotte the California round stingray has become pregnant with three or four pups despite the lack of male rays!
Before we get into this mystery, let’s learn a little more about Charlotte. She is a round stingray with brown and yellow muddled spots. This type of stingray can be anywhere from 20 to 55 centimeters in length. Most round stingrays are found near California or in the eastern Pacific Ocean. They like to eat all types of invertebrates, like shrimps and crabs. Round stingrays are usually pregnant for 3-4 months before giving birth to up to six pups. Now that we know more about Charlotte, let’s get back into uncovering this scientific phenomenon.
The news of Charlotte’s pregnancy caught the attention of many online and it continued to snowball when the head of the aquarium suggested that the stingray could have been impregnated by one of their sharks.
While this was a very popular theory amongst those on social media, there are actually a few more scientifically reasonable ways for a ray to become pregnant without males.
The director of Team ECCO, Brenda Ramer, explained that while some rays can store sperm, there is no chance Charlotte could be pregnant this way, because no male stingrays have ever been in her tank. But wait, there were male sharks in her tank. There were two white spot bamboo sharks that had shared the tank with Charlotte last year. For some male sharks, they mate with females by biting them, so when the team found that Charlotte had some bite marks, the whole scenario just got more confusing.
If you’re still wondering if a shark can actually breed with a stingray, think about it ilke this: according to Dr. Noah Bressman, “sharks and rays are as distantly related as humans and snakes, so a snake knocking up a human is just as likely as a shark knocking up a ray” (Bluesky). In short, their DNA is simply incompatible.
So knowing that cross-species hybrids are plausible but extremely rare, we turn to a more likely explanation. While sexual reproduction is the norm for rays, some can occasionally pull off something different. They have this asexual reproduction method called parthenogenesis, which means “virgin birth.” This uncommon method lets them develop embryos without needing sperm. It’s not unheard of, though – this phenomenon “has been observed in more than 80 vertebrate species, many of which are fish and reptiles (Forbes).
As of right now, there are not any updates from Team Ecco regarding Charlotte’s pregnancy. They’ve posted an image of her ultrasound on their Instagram and some other cute videos as well. Hopefully Charlotte has a smooth delivery!
Sources:
Hobson, M. (22 February 2024). This stingray is about to have a ‘virgin birth’. Scientists explain how. Discover Wildlife. https://www.discoverwildlife.com/news/stingray-virgin-birth-parthenogenesis
Large, H. (13 February 2024). Shark-Ray Hybrid? Aquarium Suggests Shark May Have Impregnated Its Lone Stingray. IFL Science. https://www.iflscience.com/shark-ray-hybrid-aquarium-suggests-shark-may-have-impregnated-their-lone-stingray-72919
Murray, C. (14 February 2024). No, Sharks Cannot Impregnate Stingrays – As North Carolina Aquarium Investigates Mysterious Pregnancy. Forbes. https://www.forbes.com/sites/conormurray/2024/02/14/no-sharks-cannot-impregnate-stingrays-as-north-carolina-aquarium-investigates-mysterious-pregnancy/?sh=6b7774aa28ed
Whitehead, B., Berger, J. (17 February 2024). ‘Miraculous birth’ expected from stingray with no mate, possible impregnated by shark. ABC 13 News. https://wlos.com/news/local/stingray-miracle-birth-expected-team-ecco-shark-lab-hendersonville-aquarium-parthenogenesis-possibly-impregnanted-shark-no-male-mate-clone-female-charlotte-jurassic-park#
