In a tiny gully on a tiny island in the vast Pacific Ocean lives a tiny creature found nowhere else on the planet.
In August, a crack anti-extinction team flew to Norfolk Island in a last-ditch bid to save the rare animal – a critically endangered snail that is smaller than a pinky fingernail and covered with yellow fuzz.
Dr Isabel Hyman, a malacologist from the Australian Museum, has spent her career studying snails. Her eyes light up when she describes the little gastropod and its “beautiful golden hairs”.
“They’ve got a little domed shell, and they’re quite small, only about seven millimetres across in shell width,” Hyman said. “There are ribs on the shell and from every rib, there are little fine hairs that come out from the shell. We’re not sure exactly what the function of the hairs is, but in other species with hairy shells, it’s often to do with moving around in a really moist environment.”
Meet the Norfolk Island hairy snail (Fanulena imitatrix). Its only known home is a 10-20 square-metre patch of rainforest in Selwyn Reserve, land owned by the federal government on the western side of Norfolk Island. Here, where pine trees grow in the rainforest, the mysterious mollusc lives under the bark of fallen branches and logs on the forest floor.
But the hairy snails are under threat from feral rats and chickens, invasive Argentine ants and the pesticide used to control the ants, and the drying effects of climate change. Norfolk Island Regional Council has found the ants in the reserve, but refrained from spraying for fear of wiping out the snails.
The population has plummeted. In August last year, timed surveys found 68 live hairy snails. That dropped to 50 by November, 12 in February this year, and four in May, using the same methodology. The number of empty shells climbed, in a sign of increased mortality.
Concerned, Hyman asked for a more thorough search. The comprehensive survey, conducted by national park ranger Sam Burridge from Parks Australia, Western Sydney University researcher James Roberts, and Simon Brown from Taronga Zoo in late July, found just 24 live specimens in about two hours.
The snail’s spiralling decline prompted a mercy dash to save the species – within a month, Hyman and Taronga zookeeper Tarryn Williams Clow were on a plane to retrieve specimens for a breeding program, accompanied by this masthead.
This followed a successful release of another rare snail endemic to Norfolk Island – the Campbell’s keeled glass-snail (Advena campbellii) – after a captive breeding program at Taronga Zoo from 2021 to 2025. The project took several years of trial and error to ensure the snails would both survive and reproduce.
“When we first brought our previous species into the zoo, we were very aware that it was some of the very last remaining of its species,” Williams Clow said. “There was a nervousness that any changes we made within their habitat may be detrimental to their survival, so we approached it very cautiously, and sometimes maybe too cautiously.”
The mission to save the hairy snail aims to move faster, so the team has also collected specimens of small sculptured glass-snails (Fanulena insculpta), a closely related species that is widespread on Norfolk Island. This species will be used as a surrogate, allowing the Taronga zookeepers to trial changes to habitat, humidity and diet with lower stakes.
“They’re kind of the little guinea pigs, but they’re going to play a really important role with how our target species goes,” Williams Clow said.
In late August, the team discovered 20 live hairy snails in a timed survey and 73 in the comprehensive search, providing more reason for optimism than the previous month.
Nearly two weeks later, Williams Clow took 30 hairy snails back to Taronga for the breeding program, along with about 20 of the surrogates. All snails have adapted well and started to give birth to live young, she said.
Norfolk Island, a rocky outcrop about 1500 kilometres east of the Australian mainland, is known for its marine biodiversity but is also a critically important global hotspot for land snails.
Burridge said there were about 60 unique snail species recorded on the island.
“We’ve got other snail species that only exist in palm forests, and other snails that only exist arboreally in the trees,” Burridge said. “There is a large range of native tree species here on Norfolk Island, and that is reflected as well in the habitats that the snails like themselves.”
The hairy snails are part of a genus endemic to the island. Of the six original species, three were extinct and Fanulena imitatrix was the rarest of the remaining three, Hyman said.
Hyman said the snails played a key role in the ecosystem, breaking down the leaf litter and providing food to other native animals.
Caitlin Fitzsimmons and Audrey Richardson travelled to Norfolk Island as guests of the Australian Museum.
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