Thousands of ‘Glow-in-the-Dark’ Snails Reintroduced to French Polynesia in Efforts to Save Species from Extinction
On Tuesday, November 18th, 2025, the team behind a decades-long zoo project celebrated their latest milestones in the recovery of the ‘extinct’ Partula snails in French Polynesia. Over 7,000 zoo-bred Extinct in the Wild and Critically Endangered Partula snails were reintroduced to four islands, making it the largest release of the finger-nail sized snail species and subspecies to date.
In order to monitor the recovery of the snails, conservationists dotted the shell of each one with a small dab of white UV reflective paint, which glows blue under UV light. As the snails are most active at night, the paint helps the team find released snails and track their progress.
During the releases, the team made an exciting discovery – an unmarked, juvenile Partula varia. This is the first wild-born member of this reintroduced snail species to be spotted in over 30 years. This discovery is proof that the Partula species is not only surviving on their native island of Huahine, but that they are successfully breeding. This is a momentous milestone for the programme.
This exciting find is a promising sign for the recovery of the species and comes less than a year after the reclassification of another Partula snail species – Partula tohiveana – from Extinct-in-the-Wild to Critically Endangered on the IUCN Red List of Threatened Species, the global assessment of extinction risk.
The team also found the first evidence of wild-born Partula tohiveana living outside of their original release area on their native island of Moorea. This indicates that the tropical snails are not only continuing to thrive, but also expanding their range.
The team is hopeful that future surveys and reintroductions will lead to more discoveries of wild-born snails, including Partula varia, and allow more species and subspecies to be downlisted.
These snails were part of carefully managed annual reintroductions, led by ZSL conservationists, which has coordinated the release of almost 40,000 snails over the last ten years. The snails, reared at London and Whipsnade Zoos, Akron Zoo, Bristol Zoological Society, Detroit Zoo, Disney Animal Kingdom, Marwell Wildlife, the Royal Zoological Society of Scotland, Riga Zoo, Saint Louis Zoo, Sedgwick County Zoo, Woodland Park Zoo, Wuppertal Zoo, and Zoo Schwerin, traveled more than 15,000km to the islands.
The UV-reflective paint not only helps conservationists find the snails nestled among the leaves and branches, but it also allows them to quickly tell apart released snails and their wild-born descendants.
Paul Pearce-Kelly, London Zoo’s Senior Curator of Invertebrates and leader of the international Partula conservation programme, expressed his excitement about the progress made in the recovery of these precious snails. He said, “This progress is decades in the making. We are not only celebrating the largest release of Partula snails in history, but also the results of over 30 years of dedicated work by conservation zoos and the French Polynesian government to enable the recovery of these precious snails in the wild.”
He also emphasized the importance of preserving all species, stating, “Wildlife globally faces unprecedented challenges, and every single species is a precious part of the interconnected web of ecosystems that we all rely on – so today’s news is not only a moment of hope for these snails, but for nature and people globally.”
Also known as Polynesian tree snails, these precious molluscs play an important role in the health of their forest ecosystems. By eating decaying plants and fungi, they help prevent the spread of disease and cycle important nutrients through the food chain.
The wild populations of Partula snails were decimated in the 1980s and early 1990s by the introduction of the invasive and carnivorous rosy wolf snail (Euglandina rosea) to control numbers of the previously introduced African giant land snail (Lissachatina fulica). In the early 1990s, the last remaining individuals of 15 Partula species and subspecies were rescued by conservationists, launching the international programme to breed these snails and recover their wild populations.
Every visit to London and Whipsnade Zoo supports ZSL’s global conservation work, including through the Extinct in the Wild Action Partnership. Visitors can see Extinct-in-the-Wild Partula snails and learn about their reintroduction efforts at the Zoo’s Tiny Giants invertebrate house. For more information, visit www.londonzoo.org.
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