Identification. Gainj is the name for approximately 1,500 people who distinguish themselves from their culturally similar neighbors on the basis of language and territorial affiliation.
Location. The Gainj live in the Takwi Valley of the Western Schrader Range in Papua New Guinea's Madang Province. On the northernmost fringe of the central highlands, the valley covers approximately 55 square kilometers, centered at 144°40′ E and 5° 14′ S. The area receives almost 500 centimeters of rain annually, with the heaviest rainfall occurring from December to April. The mean daily temperature, 22-24° C, varies little across seasons.
Demography. The 1,500 Gainj live in approximately twenty widely dispersed local groups, which vary in size from about 30 to 200 individuals. Local groups are ephemeral, with a half-life of about two generations; a continuous process of fission and fusion maintains the total number of groups at a fairly constant level. In recent years, the population growth rate has not been significantly different from zero, except for a brief period of growth following the first major influenza epidemic in 1969. Population size appears to be maintained by low fertility and density-dependent mortality. Life expectancy at birth is 29.0 years for females and 32.4 years for males; infant mortality is about 165 per 1,000 live births, with a slightly higher rate for females than for males.
Linguistic Affiliation. Gainj is classified with Kalam and Kobon in the Kalam Family of the East New Guinea Highlands Stock of Papuan languages. Many Gainj are multi-lingual, most commonly in Kalam, although men are also likely to speak Tok Pisin, and some schoolchildren speak Pisin and some basic English.