ABSTRACT
This chapter examines kin effects on mortality and fertility rates in the Ache population. The sex ratio of children produced and raised is an interesting problem in kin investment. For the most part, parents are expected to invest in offspring of whichever sex will give the highest fitness return for investment. The chapter aims to examine whether kin investment patterns can be detected through their life history effects, and to look at a few special topics that include investment by individuals other than parents to their juvenile offspring. Ache women experience a complete cessation of all reproductive function about two-thirds of the way through their expected adult life span. The lack of a relationship between the presence of some living kin and a life history trait, and the strong relationship found when looking at other kin, is likely to eliminate some possible interpretations.
