Just 11 survived after a predator introduced to fight garden pests nearly wiped them out: Hawaii’s rare tree snails return to the wild after 33 years

A creature barely three-quarters of an inch long has taken more than three decades of scientific effort to bring back to the forests of Hawaii. The O‘ahu tree snail, a species once considered lost in the wild, is slowly getting another chance after conservationists rescued the last 11 known individuals in 1991 and spent years breeding them in captivity. The species, Achatinella fuscobasis, returned to its natural habitat in December 2024, but its comeback also highlights a troubling conservation mistake: a predator introduced to control an invasive garden pest became one of the biggest threats to Hawaii's native snails.The first group of these endangered snails was released on December 10, 2024, into a specially prepared enclosure in the Honolulu Watershed Forest Reserve in the Ko‘olau Mountains on O‘ahu. The reintroduction, announced by Hawaii's Department of Land and Natural Resources (DLNR) on December 18, marked the end of more than 33 years in captivity. It was also the result of nearly half a century of conservation partnerships, research and efforts to prevent the species from disappearing permanently.How a pest-control experiment turned into an ecological threatThe story of...