The Oahu tree snails are a classic example of the devastation of the native fauna and flora of the Hawaiian Islands that has occurred following human settlement of the archipelago. All 41 species of the genus Achatinella are federally listed as endangered. Oahu tree snails are diverse in patterns, colors, and shapes but all average about 3/4 inch in length. These small snails have a smooth, glossy shell, which is generally conical in shape. These nocturnal snails are found on native trees and large bushes, where they graze fungi from the surfaces of leaves. Adults have both male and female parts (they are hermaphrodites) and give birth to live young. Young are live born, ranging from 3 to 4 millimeters (mm), growing 16.7 to 20.4 mm in length, and live around 11 years (Severns 1981 in USFWS 1992, p. 17). One to four young are born to a hermaphroditic adult each year, with reproductive maturity ranging from five to seven years old. Oahu tree snails are today restricted to mountainous forests above 500 meters.