Extinct in the Wild Snails Return Home

Over 5,000 snails have been returned to the Polynesian Islands on which their ancestors went extinct almost 30 years ago. This makes for the largest single reintroduction of the species. The snails were bred at a number of conservation zoos across the globe in an effort to ensure the survival of their species.

Thousands of the partula snails were reared at London and Whipsnade Zoos, the Royal Zoological Society of Scotland and St Louis Zoo before being flown almost 15,000km back to the islands of Moorea and Tahiti.

ZSL’s Curator of Invertebrates, Paul Pearce-Kelly, who coordinates the collaborative Partula conservation programme, said: “Despite their small size these snails are of great cultural, ecological and scientific importance – they’re the Darwin’s finches of the snail world, having been researched for more than a century due to their isolated habitat providing the perfect conditions to study evolution.

“This collaborative conservation initiative is, without a doubt, helping to bring these species back from the brink of extinction and shows the conservation power of zoos to reverse biodiversity loss. With nature across the world increasingly under threat, these little snails represent hope for the world’s wildlife.”

Scientists undertake significant work before returning the snails to the wild. Each has a dot of UV reflective paint which makes them glow under torchlight. This allows conservationists to easily spot them at night as they emerge from the trees.

During this most recent release eight species and subspecies of partula snail were returned to the wild. Their IUCN classifications range between Extinct-in-the-wild, Critically Endangered or Vulnerable.

Partula snails are also known as Polynesian tree snails. They play a key role in the ecosystem by eating decaying plant tissue and fungi. Their return to the forest is helping to restore ecological balance in the ecosystem.

Their demise during the 1980s and 90s was brought about through the introduction of the invasive predatory rosy wolf snail (Euglandina rosea) which was introduced as a control measure for  a previously introduced alien species, the African giant land snail (Lissachatina fulica). Instead the predatory wolf snails primarily hunted local snail species.

Throughout the early 1990s London and Edinburgh Zoos rescued the few remaining partula snails in the wild. Working in collaboration with 15 zoos they began breeding 15 species of snail.

Paul added: “After decades of work caring for these species in conservation zoos – and working with the Direction de l’environnement to prepare the islands for their return – we began releasing Partula snails back into the wild nine years ago. 

“Since then, we’ve reintroduced over 21,000 Partula snails to the islands, including 11 Extinct-in-the-wild species and sub-species: this year’s was the largest reintroduction so far, thanks to the incredible work of our international team efforts with collaborators, including mollusc specialist Dr Justin Gerlach of Peterhouse, University of Cambridge.”