Partula snails are a family of nail-shaped mollusks native to French Polynesia. For a long time, these creatures were scientifically and culturally important to researchers and to native (human) populations – which is why their extinction at the end of the 20th century led to a global, systematic project to bring them back.
So far, 2025 has been a great year for the Partula snail. In the spring, a subspecies of the family was reclassified from extinct-in-the-wild to critically endangered on the IUCN Red List of Threatened Species. Now, the global collaboration has announced that it has returned more than 7,000 Partula snails to their island homes this year alone. According to a press release from the Zoological Society of London (ZSL) on November 13, it is the group’s largest release since 1991, when the breeding program began.
The snails’ comeback also speaks to the value of carefully planned, long-term conservation projects. That said, being overly cautious never hurts when it comes to conservation — which is why the researchers left a little souvenir on their shells: a tiny drop of white UV reflective paint — basically glow-in-the-dark paint. ZSL said this will help experts determine the health of night snails in the dark.
Why did Partula snails almost go extinct?
At the end of the 20th century, Partula snails were almost exterminated due to an ironic but predictable human error. At that time, a carnivorous snail species was introduced to the Polynesian islands to control another invasive species – leaving the native Partula snails caught in the crossfire.
It was devastating from a scientific perspective, but each species’ shells were an important part of the island nation’s cultural identity, meaning that “the loss went beyond damaging fragile ecosystems – it was also a loss of Polynesian heritage,” ZSL noted in an introductory page to the conservation project.
At the time, the situation appeared quite hopeless; Scientists were able to save only nine individuals of one subspecies in 1991.
a great comeback
But this has apparently changed for the better, as the collaboration has managed to release more than 17,000 snails back into the wild over the past 30 years. Some of these snails had to travel more than 9,000 miles (15,000 kilometers) to get back home. But initial assessments have shown that the snails have adapted to the infection well.
For example, during the release, the team observed a baby Partula snail without UV paint – that is, the snails were already reproducing in their native environment. In addition, the team also used this opportunity to investigate the reclassified Partula subspecies, which, to their pleasant surprise, appeared to thrive inside and outside their original release range.
“These mollusks play a vital role in the health of their forest ecosystems, eating decaying plants and fungi, reducing the spread of disease and cycling vital nutrients through the food chain,” Justin Gerlach, a researcher at the University of Cambridge in the United Kingdom, explained in the statement. “By restoring wild populations, we can improve the condition of forests.”
“Wildlife globally faces unprecedented challenges, and every single species is a precious part of the interconnected web of ecosystems on which we all rely,” said ZSL researcher Paul Pearce-Kelly, who leads the International Partula Conservation Programme. “So today’s news is a moment of hope not only for these snails, but for nature and people globally.”