Charlotte, the stingray without a boyfriend, is pregnant

Charlotte, a rust-colored stingray the size of a serving plate, has spent most of her life gliding around the confines of a storefront aquarium in North Carolina’s Appalachian Mountains.

It’s 2,300 miles (3,700 kilometers) from its natural habitat beneath the waves off Southern California. And she hasn’t shared a tank of water with a male of her own species in at least eight years.

The aquarium’s owner said nature found a way, though: The stingray is pregnant with four babies and could give birth within the next two weeks.

“Here’s our daughter saying: ‘Hey, Happy Valentine’s Day! Let’s get some puppies!” said Brenda Ramer, general manager of the Aquarium and Shark Laboratory on Main Street in downtown Hendersonville.

An expert on stingrays said it would be impossible for Charlotte to mate with one of the five smaller sharks that share the same tank, despite reports suggesting this was the case after Ramer joked about a possible interspecies link.

The small aquarium is run by Team ECCO, Ramer’s nonprofit educational organization, which encourages local school children and others to become interested in science.

His biggest lesson now concerns the process of parthenogenesis: a type of asexual reproduction in which offspring develop from unfertilized eggs, meaning there is no genetic contribution from a male.

This mostly rare phenomenon can occur in some insects, fish, amphibians, birds, and reptiles, but not in mammals. Documented examples include California vultures, Komodo dragons, and yellow-bellied water snakes.

Kady Lyons, a research scientist at the Georgia Aquarium in Atlanta who is not affiliated with the North Carolina aquarium, said Charlotte’s pregnancy is the only documented example she knows of for this type of round stingray.

But Lyons isn’t shocked at all. Other species of sharks, stingrays, and stingrays (three animals often grouped together) have had such pregnancies in human care.

“I’m not surprised because nature finds a way to make this happen,” he said.

To be clear, Lyons said these animals did not clone themselves. Instead, the female’s egg fuses with another cell, triggering cell division and leading to the formation of an embryo.

The cell that fuses with the egg is called the polar body. They are produced when the female lays eggs but are not generally used.

“We don’t know why this happened,” Lyons said. “It’s just a really neat thing, they seem to be able to do it.”

Ramer said he and others at the nonprofit initially thought Charlotte had a tumor when they noticed a lump on her back that “popped like a cookie.” However, her pregnancy was revealed on ultrasound.

“We all said, ‘Close the back door.’ “There’s no way,” Ramer said. “We thought we were overfeeding him. But we were overfeeding him because he had more mouths to feed.”

Charlotte currently lives in a tank of approximately 2,200 gallons (8,300 liters), or nearly the size of a construction dumpster. Ramer said they hope to purchase a tank nearly twice that size to house Charlotte’s hatchlings. They also want to put live cameras so people can see them.

“It’s very rare for this to happen,” Ramer said. “But this is happening in the middle of the Blue Ridge Mountains in rural North Carolina, hundreds of miles from the ocean.”

Lyons said that the claim that Charlotte could have been impregnated by a shark was impossible. In addition to being different sizes, the animals do not match anatomically. So is their DNA.

“We need to make it clear that no shark ray nonsense is happening here,” said Lyons, whose graduate studies focused on species.

Round stingrays like Charlotte are abundant along the Pacific coasts of Southern California and Mexico and are often found on the sandy bottom of the ocean near the coastline.

In the wild, they are usually the size of a small dinner plate and their name comes from their circular shape. They come in all shades of brown. They eat small worms, crabs, and molluscs, and are preyed upon by certain species of sharks, seals, and giant sea bass.

They are well known to humans for their painful stings, which are usually caused by a beachgoer stepping on them. Lifeguards in Southern California encourage people to practice the so-called stingray scramble while wading, largely because of the round stingrays.

Lyons finds this genre fascinating. For example, embryos in the uterus are bathed in uterine milk, which provides nutrients to help them develop.

“I’m glad the round stingray is getting the media attention it deserves,” Lyons said. “They may not be as sexy as the white shark, but they do some really cool things.”