Boa constrictor gives birth to 14 baby snakes after living alone for nearly a decade

Ronaldo, a 6-foot Brazilian rainbow boa constrictor kept at a school in England, was thought to be male — until the snake gave birth to 14 babies last month.

The boa had not had contact with another snake for nearly a decade, so she appears to have undergone a natural process of asexual reproduction called parthenogenesis. The term is derived from the Greek words for “virgin birth.”

The school said this is the third documented case of this type of birth that it is aware of from a Brazilian rainbow boa in captivity.

Ronaldo lives at the City of Portsmouth College,an academic and vocational school for 16- to 18-year-olds in southern England, where the snake is used to help train students about how to care for animals.

“I received a call from a colleague of mine asking me why I had released some small snakes in with Ronaldo,” said Pete Quinlan, an animal technician at the college who has cared for the snake for the last nine years.

Quinlan said his initial thought that day, June 21, was that there had been a mistake. Although it was his day off, Quinlan went in and immediately recognized that the snakes with Ronaldo were baby rainbow boa constrictors.

“I was completely puzzled by it,” he said, noting that he has worked with reptiles for over 50 years.

Ronaldo's boa constrictor babies. City of Portsmouth College

“I’ve kept literally thousands of snakes within that time and bred a lot of snakes as well,” Quinlan added. “I’ve never heard of it before.”

In a news release, the college described the event as a “miracle birth,” though some snakes and other animals — including crocodiles and honey bees — have been known to produce offspring asexually.

Parthenogenesis occurs when an embryo develops without being fertilized. The process is especially rare for vertebrates, including snakes.

Unlike sexual reproduction, which requires sperm to fertilize an egg, parthenogenesis can involve byproducts of the process that creates eggs, called polar bodies, which are used to fill that gap. These cells get combined back into the eggs, giving the embryos two similar — but not identical — sets of DNA.

Parthenogenesis can also occur when sex cells duplicate then join back together; this process creates clones of the mother, though it primarily occurs in plants, not animals.

Researchers are still investigating why parthenogenesis occurs in animals, and how frequently.

Baby rainbow boa constrictors from Ronaldo, produced via parthenogensis. City of Portsmouth College

Quinlan said some researchers believe that snakes undergo parthenogenesis when females do not have a mate for most of their lives.

In recent years, several other reports have emerged of animals reproducing asexually in captivity. Last year, a shark at the Brookfield Zoo in Illinois gave birth to a pup via parthenogenesis, after having no contact with a male shark for at least four years. And a 2021 study found that California condors, a critically endangered bird species, reproduced asexually in captivity even though they had access to mates.

A stingray named Charlotte, who became pregnant via parthenogenesis at an aquarium in North Carolina, died on Sunday. The aquarium announced last month that the ray — whose story even became the subject of a “Saturday Night Live” sketch — was no longer pregnant and had been diagnosed with a rare disease.

Quinlan said he initially got Ronaldo from the Royal Society for the Prevention of Cruelty to Animals, a charity that supports animal welfare. A vet had said that Ronaldo was male, and Quinlan never questioned that. It’s harder to determine a snake’s sex when they’re adults than when they are babies, he said.

Ronaldo is a “very popular snake” at school, Quinlan said, adding that the students had never taken care of newborn snakes before, so this should be a “really good experience” for them.

Evie Allen,a student at the college who works with Ronaldo, said she was “shocked” and “confused” when a friend told her that the snake had given birth.

Evie Allen and Ashleigh Nicole, a learning assistant at the City of Portsmouth College, hold one of the baby snakes and a snake skin.City of Portsmouth College

“I genuinely thought he was joking,” she said.

The college intends to keep one or two of the baby snakes, and to care for the rest until they have had a few meals and are healthy enough to go to new homes.

Ronaldo’s story has garnered attention around the world.

“I didn’t expect it to go quite as viral as this has,” said Paula Hetherington, who manages marketing and communications for the college.

“If you Google Ronaldo the snake now, it seems to be more popular than Ronaldo the footballer,” Quinlan said.

Elysee Barakett

Elysee Barakett is a health intern at NBC News.