Sharing among sons: resource-dependant sibling competition for reproduction and inheritance among the Arsi Oromo

Mhairi Gibson, University of Bristol

In this paper I explore how resource availability can influence kin competition and support among 222 patrilineal Arsi Oromo agropastoralists in Southern Ethiopia. Sibling configuration (number of older and younger, male and female sibs) is shown to influence both reproduction and inheritance in males [in land, out-migration, marriage payments and surviving offspring]. Overall, sisters have a positive influence on their younger brothers’ reproductive lives, by increasing their first marriage payments, and total number of wives. Brothers, for the most part appear to be in competition for heritable resources, including land. In the poorest households, number of brothers is positively associated with an increased risk of migrating out of the village to seek employment. However, in the wealthiest households there is evidence for support from within the patrilineage, where younger brothers (paternal uncles) are associated with an increase in the number of surviving offspring.