The loneliest snail’s relatives, like Achatinella mustelina (above), are also critically endangeredDavid SischoBy Guy Dinmore in Honolulu, HawaiiIt’s the loneliest snail on the planet. Just one individual of the species is known to exist. He or she – for snails are hermaphrodites – is 9 years old, has borne no offspring so far and lives quietly in...