Mystery pregnancy at aquarium as shark seems head over tail for stingray
Originally thought to be a ‘virgin birth’, bite marks on the fish’s body could point to its tank companion
STUCK in a small-town aquarium thousands of miles from its natural habitat, a stingray known as Charlotte has lived an uneventful life.
Yet the rust-coloured fish has found itself at the centre of a “once-in-a-lifetime mystery” – at least according to staff looking after it at the Aquarium and Shark Lab in Hendersonville, North Carolina.
Despite not having encountered a male of the same species in the past eight years, Charlotte is expected to give birth to pups in the next fortnight.
It could be that Charlotte is to become the first stingray proven to have reproduced asexually – a process known as parthenogenesis, previously seen in other sharks, skates and rays but aquarium staff have put forward an alternative theory.
They claim the key to the mystery may lie in strange marks on its body – bites from a white-spotted bamboo shark it shares a tank with.
April Smith, the aquarium director, said: “We started to notice bite marks on Charlotte, but saw other fish nipping at her, so we moved [the] fish, but the biting continued. Then our light bulb went off – sharks bite to mate. Did one of our young males mate with her?”
Experts have poured cold water on the idea of a cross-species romance.
Prof Steve Simpson, a marine biologist at the University of Bristol, said a stingray-shark relationship would be equivalent to a human mating with a camel but did not rule out the theory.
“That’s probably the least likely of the options,” he said. “Nearly half a billion years ago they had a common ancestor, which in evolutionary terms is a very long time ago.
“We’re more recently related to camels than sharks are to rays.”
Charlotte may have stored sperm from a previous encounter with a male, Prof Simpson added, although he said it was most likely it had reproduced asexually.
“That’s my bet,” he said. “If I had £100 I’d put £70 on that. I might put a £5 flutter on the shark-ray just for fun.”
“The beauty of this story is that we get to find the answer out – it’s not a mystery forever in terms of what happens,” he added.
Dr Kady Lyons, a research scientist at Atlanta’s Georgia Aquarium, is also sceptical of claims that Charlotte will give birth to a shark-stingray hybrid.
“We should set the record straight that there aren’t some shark-ray shenanigans happening here,” she said, arguing that the creatures simply would not match up anatomically.
Dr Lyons believes that Charlotte has reproduced via parthenogenesis, telling the Associated Press: “I’m not surprised, because nature finds a way of having this happen.
“We don’t know why it happens. Just that it’s kind of this really neat phenomenon that they seem to be able to do,” she continued. “I’m glad the round stingray is getting the media attention that it deserves – it’s not necessarily as sexy as a white shark.”
Aquarium staff initially feared that Charlotte had developed cancer when they noticed a lump on its back, but a subsequent ultrasound revealed is is pregnant with at least two pups.
The stingray lives in a 2,200-gallon tank, but staff hope to move it to a habitat roughly twice the size to accommodate its offspring, when they arrive in the coming weeks.
‘We started to notice bite marks on Charlotte. Sharks bite when they mate’