- The Obô giant snail, found only on the islands of São Tomé and Príncipe off Central Africa, can grow up to 6.16 inches long — roughly the size of a croissant.
- The species is endangered, producing only three to six eggs a year, and is threatened by habitat loss, disease, overharvesting and invasive predators.
- Conservation groups Mossy Earth and Flora & Fauna are running a dedicated breeding and habitat-restoration program, including genetic sampling to guide future protection efforts.
A snail the size of a croissant is at the center of a conservation effort so delicate that biologists say every single sighting still feels like a small miracle.
In April, students aged 8 to 14 joined National Geographic’s Explorer Classroom for a virtual visit with biologist Martina Panisi, who stood in a tropical forest on the islands of São Tomé and Príncipe, off the coast of Central Africa, holding one of the giant snails in her gloved hands.
“The Obô giant snail,” Panisi told the Explorer Classroom, cradling it carefully. “It’s my favorite species in the world. So, every time I find it, I’m like, ‘Whoa, they are still here. They’re still among us!'”
The snail she held was a juvenile — the species can grow up to 6.16 inches long. Panisi explained that Obô giant snails are hermaphrodites, capable of producing eggs as big as an olive.
“They are very special,” she said. “They produce only three to six eggs per year, and that’s why they’re also endangered because their reproduction is very slow — and they grow very slow.”
The Obô giant snail is found only in the tropical forests of São Tomé and Príncipe. Once one of the most abundant species on the islands, it has faced mounting threats over recent decades from habitat degradation, overharvesting, an unidentified disease, and predation by non-native animals including wild pigs, rats, cats, dogs, genets and monkeys.
The snails play a quiet but important ecological role, Panisi said.
“These snails, together with other living beings in the forest, help by eating the litter,” she said. “They help decompose [them] and then the nutrients go back inside the ground, and the trees can use the nutrients again to grow healthy and strong. So we need to thank these guys for keeping this forest healthy.”
Panisi has spent more than six years working alongside local conservationists at a dedicated giant snail conservation center at Jardim Botânico do Bom Sucesso on São Tomé Island. Mossy Earth, a UK-based social enterprise, has partnered with local conservationists on forest surveys and habitat protection, and has helped gather genetic data from the snails.
“By processing this data, we hope to obtain a better understanding of the migration history of the Obô giant snail across the two islands,” Mossy Earth said in a statement on its website, adding that the insights can help “establish conservation priorities” and preserve genetic diversity as the snail’s environment changes.
Flora & Fauna, the conservation charity backed by Sir David Attenborough, has also stepped up its work on the islands, which it describes as the “Galapagos of Africa.”
“After 30 million years of isolation, life here has evolved into something truly extraordinary,” Flora & Fauna wrote on its website. “If we don’t act now to protect what’s left of these precious native forests, entire species will be wiped out.”
