The Partula snails, of some South Pacific islands, may be the rarest in the world, but they are fighting for survival. Giant African snails were introduced to the islands accidentally, but became a farm pest. So, a meat-eating snail was introduced to control them, but preferred to catch the smaller Partula snails, which are 4 in (2 cm) long. The species is now rare, and it is threatened by habitat loss too, but Partula snails are being bred in captivity now, to try and save them.