The Partula snail, also known as the Polynesian or niho tree snail, is a tiny snail that was once a common sight in Tahiti. The snail is not much bigger than the rubber end of a pencil. Its body is bumpy and brown, and its antenna is almost translucent. These snails play an important ecological role in French Polynesia because they eat dead plant tissue and debris. This helps maintain the health of the forests. More than 80 recorded species of Partula snails; however, 51 are extinct, 11 are extinct in the wild, and 15 are critically endangered.
About 30 years ago, the snail was eaten out of existence by two larger snails: the giant African land snail and the rosy wolf snail, which were introduced to the island by humans. The rosy-wolf snail had been introduced to control the African giant land snail population. Unfortunately, the rosy-wolf snail negatively impacted the Partula as they could chase down the scent of their prey’s slime trails at three times the speed of a normal snail.
Some of the remaining Partula snails were saved and put into captivity to breed and help restore their populations. Conservation experts from various zoos, including London and Whipsnade zoos, the Royal Zoological Society of Scotland and Saint Louis Zoo in the United States, have worked tirelessly over the past decade to reintroduce the Partula snails back into the wild. The Zoological Society of London (ZSL) is actively breeding, releasing and monitoring snails on four islands and has so far reintroduced 11 previously extinct wild species. Over 21 000 snails have been reintroduced back into the islands thanks to their work.
This year, ZSL participated in the largest-ever release of extinct-in-the-wild species. Zookeepers transported 5522 Partula snails to the French Polynesian islands of Moorea and Tahiti. The snails were marked with a dot of red UV reflective paint that will glow under UV torchlight. This will help conservationists monitor the populations when the snails are most active at night. This year’s conservation efforts saw eight species and sub-species reintroduced.
The team has pioneered the world’s first predator-proof snail reserves on the Society Islands. Experts say that the rosy-wolf snail shouldn’t cause a problem to the reintroduced Partula snails because their populations have declined significantly and have been replaced by a new predator, the New Guinea flatworms. They are not too worried about the new predator as they are hoping to re-establish the Partula snails back into the trees, and the flatworms will stay on the ground.
Right now, it is hard to see how well the reintroduced snails are doing, but experts believe once they have established themselves in the wild, ecological balance within the islands will be restored. The snails bred in zoos for generations have adapted well to being back in the forests, so there is confidence that these newly reintroduced snails will thrive.