Archive: Detroit Zoo Saves Snail Species From Extinction

Three-decade collaborative breeding program returns Partula nodosa to the wild

May 26, 2015


One hundred Partula nodosa snails bred at the Detroit Zoo are en route to Tahiti, effectively restoring a population that was extinct in the wild.

For nearly three decades, the Detroit Zoological Society (DZS) has been breeding this species of Tahitian land snail as part of a collaborative effort credited with saving the species from extinction.  The work began in 1989 as a project with 115 snails of five species, with the DZS concentrating its efforts on this one species and engaging other institutions to focus on the remaining four.  At one point, all the P. nodosa in the world lived at the Detroit Zoo.

“Our efforts and successful breeding of the snails resulted in the rescue and recovery of the species,” said Scott Carter, DZS chief life sciences officer.  “Currently there are six thousand individuals living in North American zoos, all descendants from the Detroit Zoo’s original small group.”

Partulid snails like the P. nodosa were once found across Tahiti and other south Pacific islands in an array of more than 125 different species.  These striped snails were used in ceremonial jewelry and decorations of indigenous islanders, and the snails served as a study group for scientists to learn more about the evolution of diversity.

Much of the Partulid snail diversity was lost due a botched attempt at “biological control”, or the control of a pest by the introduction of a natural enemy or predator.  In 1967, giant African land snails were introduced to Tahiti and other south Pacific islands to serve as a source of protein for local residents.  Some of the African snails escaped, bred very rapidly, and began eating farmers’ crops, threatening the local economy.  To control the African snails, Florida rosy wolf snails were introduced a decade later, but the wolf snails preferred to eat the Partulid snails, which caused the extinction of many of the Partulid species.

Before complete extinction, P. nodosa snails were placed at several zoos including the Detroit Zoo, where they have been maintained off exhibit in a carefully controlled environment.

“With the sufficient growth of the captive population and the establishment of a protected area on Tahiti, this species is officially on the road to being saved,” said Carter.