A particular bay in the French territory of New Caledonia is a popular swimming spot for locals and tourists alike. However, the swimmers at the Baie des Citrons in Noumea may not be thrilled to learn they've been sharing the water with a surprisingly large number of venomous sea snakes. The discovery is largely due to the efforts of a group of seven women in their 60s and 70s nicknamed the "fantastic grandmothers," reports the Guardian. None are scientists, but they struck up a relationship with researcher Claire Goiran from the University of New Caledonia and agreed to keep an eye out for the greater sea snake, aka the olive-headed sea snake. "The results have been astonishing," says Goiran in a news release. "As soon as the grandmothers set to work, we realized that we had massively underestimated the abundance of greater sea snakes in the bay."
Before the women got to work, researchers were spotting about 10 snakes per year. Now they realize the relatively small bay is home to approximately 250 of the snakes, which can grow up to nearly 5 feet long. The happy news? Nobody has even been bitten, "testifying to their benevolent disposition," says Goiran's colleague, Rick Shine of Australia’s Macquarie University, per CNN. The large number of snakes suggests they play a bigger role in the local ecosystem than previously thought, and researchers plan to investigate that next. One of the grandmothers, Sylvie Shebert, tells the Guardian she has grown to appreciate the snakes after being initially fearful. The "snakes are not aggressive, just curious," she adds. “Of course, we will never touch them.” (The bite of a sea snake can indeed be fatal to humans.)