This small ethnic group (Oak, Iguat, Iwaak, etc.) has a population of approximately 3,000 (NM 1972) dispersed in small fenced-in villages which are usually enclaves in communities of surrounding major ethnic groups like the Ibaloy and Ikalahan (1970 estimates). The characteristic village enclosing fences are sometimes composed in part of the houses with the front entry facing inward. Pig sties are part of the residential architecture. The Iwak are found principally in the municipalities of Boyasyas and Kayapa, province of Nueva Vizcaya. The subgroups are: (1) Lallang ni I’Wak, (2) Ibomanggi, (3) Italiti, (4) Alagot, (5) Itangdalan, (6) Ialsas, (7) Iliaban, (8)Yumanggi, (9) Ayahas, and (10) Idangatan.
Subsistence is based on dry cultivation of taro which is associated with complex rituals using the pig as the principal ritual animal. Focus in cropping is shifted to the cultivation of sweet potato as the staple. Some wet rice is cultivated in the flood plains of mountain streams in the lower elevations. The social organization is systemic and is based on indigenous religion marked with the use of a ritual house about which a kin-based parish is organized. Associated with the social organization and religion, membership is defined in a meat-sharing system.
Like other groups in the Cordillera, it is obligatory for an adult male to celebrate a personal prestige feast(padit) at least once in his life time. He would raise and gather a large herd of pigs for the highly complex rituals that may take several days to conclude. Pigs like other animals are only eaten within the context of rituals, and the meat is judiciously shared with all the members of the community.