Prior to the twentieth century most people lived in the foothills surrounding South West Bay, but missionization was the main catalyst for resettlement along the shores of the 9.6-kilometer-long harbor. Today the Mewun live on the northern half of the bay, the Seniang live to the south, and the unmissionized people of Laus remain farther inland in a number of small settlements. Traditionally all three groups lived in small settlements of fewer than fifty people, with separate residences for men and women arranged around a central clearing where dances and other ceremonies could take place. Children initially lived with their mothers, with boys moving into the men's house when they reached the age of 5 or 6. Since missionization, the Mewun and Seniang have settled in larger villages of 100-300 residents. Missionized villagers were required to have two houses, one for sleeping and the other for cooking, because it was considered unhealthy for residents to sleep in smoky areas. Although men and women were expected to live and sleep together, many Mewun used their two houses to preserve their traditional custom of sleeping apart; while women and children slept in the official sleeping houses, their husbands often slept in the family kitchens. This separation of the sexes has remained common up to the present. Traditional house styles with walls of black palm and thatched roofs made of tangura palm have given way in mission villages to walls and elevated floors of woven bamboo; nowadays, some families prefer corrugated tin roofs because they last longer and can be used to catch supplies of rain water.