The Fish is the Friend of Matriliny: Reef Density Predicts Matrilineal Inheritance

Reef density predicts the prevalence of matriliny in a sample of 186 societies across the world and in a sample of 59 small-scale horticultural fishing communities in the Solomon Islands. We show that this result holds even controlling for common descent by relying on variation within ethno-linguistic groups in our Melanesian micro-sample, where matriliny is ancestral. Reef density explains as much as 20% of the variation in inheritance rule across villages in the Solomon Islands. We thereby establish that reef density and, indirectly, reliance on fishing, is a robust predictor of the persistence of matrilineal inheritance. Explanations based on the sexual division of labor and on inclusive fitness arguments support our results. We also document some of the demographic consequences of matrilineal inheritance, including smaller household and village population siz.