There are fifteen villages on Nissan Atoll and three on Pinipir with populations in 1971 ranging from 80 to 337 persons. Most villages consist of one or two hamlets and houses Scattered individually or in clusters in the bush. In precontact times, settlements were smaller and, because of endemic warfare, were located strategically in the bush. Consisting of a single or double row of houses, the hamlets were originally created by colonial officials as convenient administrative units. Some villagers maintain residences both in the hamlet and near their gardens in the bush to protect them against marauding pigs. The central feature of a settlement is its men's house ( iabas ), where in the past all unmarried males over the age of 9 slept. Other men sometimes slept in the house as did male visitors to the village. Although many iabas customs are disappearing, it still serves as a clubhouse exclusively for men; in it they plan activities and gossip. Contemporary residences of traditional construction are single-room, windowless, rectangular structures with ridged, steeply sloping roofs. They are built on the ground with walls of areca-palm bark and sago-thatch roofs. Nowadays, islanders often build houses on piles and incorporate introduced Materials such as plywood, sawed timbers, concrete, and galvanized iron roofing.