First, there is a bulge on the right side of the snail’s neck, and then slowly (because everything in the snail world happens slowly) a fully formed baby snail appears, shell and all.
An adult Campbell’s glass snail gave birth to more than 20 babies last week in a quarantine facility at Sydney’s Taronga Zoo.
Although breeding in captivity was difficult, Advena camperi They’re now breeding like rabbits – or snails – and scientists are planning to bring some of them back to their only known habitat, a tiny valley on tiny Norfolk Island in the middle of the Pacific Ocean.
In March 2020, a photo taken by local citizen scientist Mark Scott arrived in the inbox of Dr Isabel Hyman, a malacologist (that’s a snail scientist to us) at the Australian Museum in Sydney, revealing that the thumbnail-sized snail was officially extinct.
“Mark was looking at a pretty large snail that he didn’t recognise and I’d seen it years ago and thought it was gone,” says Hyman, jumping with excitement as he recalls seeing the photo for the first time.
The images showed the snails’ distinctive angular shape and two-colored shells, and Hyman was pretty sure they were an “extinct” species. She and her colleagues went to the island, where Scott guided them to the site, where she turned over a rotting palm leaf and found the snails lined up in a row.
“My heart was pounding and I was so excited, but then another thought came to me: ‘We have to do everything we can to protect this island,'” she said.
From two trips to areas within the island’s national park, 40 snails were airlifted to an isolated, purpose-built captive breeding facility at Taronga Zoo in Sydney.
But the battle to save the snails and create the right conditions for them to give birth to lots of babies was just beginning.
Within six months, all the original snails had died, and for the first two years newborns were barely able to keep up with the ones that were dying off. The snails’ life span is thought to be just 10 months.
“We had told the locals we were going to return them,” Hyman says, “but we were worried that if they all died, would that be all we’d done? Would we have weakened the population even further? It would be completely useless.”
“They’re doing a lot of stuff.”
After discovering the snail, the team received grant funding from the Australian Museum Foundation, the National Geographic Foundation, the Mohammed Bin Zayed Species Survival Fund and the Australian Research Council.
Taking inspiration from other captive-breeding programs around the world, particularly in Hawaii, where several land snail species are endangered, a team of zookeepers and scientists overhauled the way they raised the snails. They made one small change at a time and waited to see the results.
They tweaked the temperature, humidity, food (calcium carbonate, oatmeal, nettle leaves, fish food, vitamin paste), feeding method, plants in the tank, etc.
In late 2023, there were only eight adult snails out of 70. Today, the population has grown to 300.
Taryn Williams-Crow is a zookeeper who leads the snail captive breeding program at Taronga Zoo.
Most of her experience in captive breeding has been with exotic mammals such as black rhinos, cheetahs, otters and tigers, so a snail would likely drastically reduce the risk of attack.
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But creating the right environment for the snails to reproduce slowly and steadily wasn’t easy.
Unlike most humans, snails don’t like to be disturbed, they like their cozy spots (under palm leaves) and seem to prefer to be active in the dark – all they seem to be missing is mood lighting, Barry White albums and Chardonnay.
But what they do to reproduce is a mystery: The snails are hermaphroditic, but no one has ever seen them mate. Williams-Crow even goes to the zoo in the middle of the night to see if she can catch them mating.
“I’ve never seen them mating because they’re nocturnal and secretive,” she says, “but I imagine they do a lot of things.”
“We know of similar snail species that have interlocking organs that come out of their necks,” Williams-Crow says, “and we think they mate, but we don’t know if they can self-fertilize.”
“One of their colleagues thinks they may have seen them doing something but disappeared as soon as they were disturbed.”
One breakthrough was the feeding method: The snails had trouble getting food from a glass dish smeared with paste, causing their mouths to pop out. Placing the food on a paper towel dramatically increased their survival rate.
Tooth removal
The Campbell’s Keeled Grass Snail is likely endangered on Norfolk Island due to the introduction of rats, habitat loss due to land clearing, and the introduction of other animals such as feral chickens.
While snail extinction may not be a hot topic, Hyman says more land snails have gone extinct than any other group of animals on Earth: The International Union for Conservation of Nature’s endangered species list includes 85 extinct mammals, 159 bird species, 32 reptiles, 60 insects and 297 mollusks, of which 190 are land snails.
Hyman said many of the extinctions of land mammals are similar to the problems faced by Campbell’s Keels’ grass snails, which were popular among rats that arrived and established in Pacific islands and enjoyed eating.
With captive breeding facilities currently at full capacity, the team has begun planning to release some of the animals on Norfolk Island, with a trial release possible before the end of the year.
Hyman has updated the IUCN’s latest version, but the site still lists the snail as extinct.
“We’ve learned a lot about them, but we never thought we’d be able to take it a step further. It’s exciting that we have the ability to do that.” [a release] now.
“They’re barely surviving… and they’ve got teeth.”
