The sledder conceived Charlotte via parthenogenesis and became a local star

A female skate living in an aquarium in a small American town will give birth to her own young, even though she has never shared her tank with a male of her species. As a result, she became a local star and attracted the attention of scholars.

Charlotte the Sled, who had resided in Henderson, North Carolina, for eight years, developed an unusual tumor around the end of November. Her pelvic keepers were initially concerned it was cancer. “It started to swell more and more and we thought it was a malignant tumor,” said Kinsel Boyette, veterinarian and deputy director of the aquarium. Such cysts are known to develop in the reproductive organs of non-mating slugs.

But the ultrasound went off like a bomb for another reason: it was eggs.

Charlotte the Sled can give birth from day to day. Parthenogenesis is extremely rare and the gestation period varies from the usual three to four months.

When she gives birth anyway, the small town is already standing on its feet. After being closed for a long period of time for maintenance, the aquarium reopened Thursday and “everyone who comes wants to see Miss Charlotte,” Boyette said.

The possibility of uniparental reproduction, i.e. without male contribution, is rare although it has been observed in many vertebrates, such as birds, reptiles and fish. But there is no record in mammals.

“When you call Jurassic Park, life always finds its way,” said Brian Legare of the Massachusetts Institute of Marine Sciences. He explained that animals that cannot mate sometimes activate a process called parthenogenesis. Small cells called polar bodies that form at the same time as eggs—and which disintegrate under normal circumstances—fuse back with the egg, creating the genetic material needed to form a viable embryo.

It's hard to say how often this happens, Legare said. Every year or two a case is reported of a shark or stingray living in an aquarium and reproducing by parthenogenesis. Something like this could happen in nature, but it must be confirmed through genetic testing.

Compared to normal pregnancies, the risk of developing health problems is increased.

Scientists point out that amphibian reproduction offers advantages in the evolution of species, but requires finding a sexual partner. “With parthenogenesis, there are also advantages. You can celebrate Valentine's Day yourself,” Legar joked.

In addition to her unusual pregnancy, Charlotte, who lives with five baby sharks, charms visitors to the aquarium thanks to her personality. “I was in the tank with her today and she was doing circles because we have a bunch of kids here and she really likes to be the center of attention. She's amazing,” Boyett said.

This type of lizard incubates eggs inside its body and gives birth to live young of up to four at a time. If Charlotte gets four newts, the aquarium hopes to be able to double the size of its tank.