The Province is the home to a number of tribes, including the Foi, who was discovered by the explorers in the 1930s. The Foi inhabit the Mubi River valley and the shores of Lake Kutubu, the area near the border of the Southern Highlands and Gulf Provinces.
The Foi divide themselves into three sub-groups: the Gurubumena, the inhabitants of the four Lake Kutubu villages (also known as “Kutubu people” or Ibumena, “lake people”), the Awamena, the Foi living along the Upper Mubi River (“above people” or “northern people”) and the Foimena (known as “true Foi people” or “lower Foi”) who reside near the junction of the Mubi and Kikori rivers.
The linguists used the term Foi to refer to all people speaking this language, and this has been adopted by the Foi themselves.
In Foi custom, all men sleep in the longhouses (Hausman) reserved only for men while their wives and children live in smaller houses around. Women are not allowed to enter the Hausman. The longhouses, typically built on the top of ridges for defensive purposes, are big constructions, around 50 meters long and 7 meters wide, erected 1.5 meters off the ground, with the peak of the roof of 5 meters from the floor, and with fireplaces on each side of a central corridor.
The Foi recognize five seasons based on the appearance of certain seasonal plants. Traditionally, during the rainy season, the Foi men would abandon their longhouses and would occupy individual bush houses, together with their wives and children, and would live on hunting. Old men would usually stay behind; no one is obliged to leave the village. Young unmarried boys would often go hunting at any time of the year. However, as most people stay away from the village during the rainy hunting season, the ceremonies such as marriage, death, and initiation as well as collective activities such as house building and fishing are not held during this time.
The Foi are recognized by their faces brightly painted in red, yellow, and black using special oil. The black color is used for warriors, red for mature men and yellow for initiates. The Foi men are renowned for their knowledge of how to produce highly valued oil from the karao tree that they call “Digaso oil”. The karao tree produces abundant clear exudate, which when reacting with oxygen, creates the viscous black oil. Mixed with charcoal and plant dyes, the oil produces the paint used in ceremonies and rituals to make the skin shine, and to protect against lice and small sores. In the past, the oil was traded with Nipa people for stone axes, with Huli for pigs, and salt from Lake Surinki in the Opene hinterland.
The Foi are also known for their body-part counting system in which different parts of the body correspond to a number. The Foi are counting from 1 to 37.