When a small brown shell appeared on a paved alley in central Hamilton in 2014, biologists initially suspected a misidentification. The Bermuda land snail (Poecilozonites bermudensis) had been presumed extinct in the wild since the early 1970s. Yet the discovery was genuine. In February 2026, Chester Zoo announced that over 106,000 released specimens now occupy six stable colonies on Bermuda's outer islands, with the species considered secure.
2014: One alley, one vanishing species
The Bermuda land snail was part of the island's endemic fauna and was displaced from its habitat throughout the 20th century. Invasive species introduced from abroad, including predators and competing snail species from Europe, consumed eggs and displaced the native snail from its habitats. Last known sightings in the wild date to the early 1970s. The species was then listed as extinct internationally on the IUCN Red List.
The 2014 discovery of a small population in a paved city alley was thus a zoological surprise: animals that had survived in an unexpected urban niche, shielded from the island's main habitats. A second discovery followed three years later in 2017: another remnant population on Port's Island, a 6.7-hectare island in Great Sound. Together, both discoveries provided the genetic foundation for the breeding program.
2016 to 2022: Breeding across three continents, 27 locations
Chester Zoo in England took the lead of the international program, working with the Bermuda government and conservation organization Biolinx Environmental Research. Snails were bred in specially constructed enclosures under controlled temperature and humidity. Their tiny size of just a few millimeters posed special challenges but also enabled large populations in small spaces. Zoos in Canada participated in additional breeding.
Between 2019 and 2022, 106,000 snails, adults and juveniles, were released at 27 locations on mainland Bermuda and outer islands. A study in the journal Oryx evaluated results: all six reintroduction sites on remote outer islands were successful. Colonies are growing, reproducing, and established. Attempts on the main island, however, all failed, researchers concluded, due to higher predation pressure from introduced species on the mainland.
A 2025 genome study sequenced the complete DNA of the Bermuda land snail, providing the scientific foundation for ongoing genetic management in captive and wild populations. Chester Zoo declared the species secure on February 2026's Reverse the Red Day, an international observance against species extinction.
The comparison: What breeding programs can achieve
The Bermuda land snail stands among other species saved by intensive conservation programs. The Iberian lynx was considered the world's most endangered cat in 2002 with fewer than 100 individuals. Through systematic protection, captive breeding, and targeted releases, the population rose to 2,401 animals by 2024. The IUCN downlisted the Iberian lynx from endangered to vulnerable in June 2024, a status marking conservation success on the Red List.
The California condor was more dramatic: only 22 remained in 1987. All were brought into captivity. The U.S. Fish and Wildlife Service began reintroductions in 1992. By 2024, 410 condors had been released to the wild. The pattern resembles both cases: when wild populations collapse, controlled breeding can buy time. Habitat conditions must improve in parallel so released animals survive.
Invertebrates rarely take center stage in such conservation attention. Mammals and birds dominate conservation success stories because they capture more public interest. That an international team of zoos spent a decade on a few-millimeter snail is unusual and sets a precedent relevant for other threatened invertebrates without public charisma.
Why the main island still awaits
Six stable colonies on outer islands represent success, but not completeness. Attempts to establish the Bermuda land snail on the main island all failed. On small, remote outer islands, invasive predators are less present or absent. On the densely populated main island, introduced rats and snail predators decimated newly released animals before they could reproduce.
For a stable long-term population, the species would need to reclaim the main island, where original core habitats lay. This would require controlling invasive species in parts of the main island, an expensive and demanding undertaking. For now, Bermuda's land snail's future depends on six island colonies. They are small and isolated, but secure for the moment.