Spread of cattle led to the loss of matrilineal descent in Africa: a coevolutionary analysis

TLDR

Matrilineal descent is rare in societies that keep large livestock, but this negative correlation alone does not prove a functional link because cultures are not statistically independent due to shared history (Galton's problem). The study tested whether acquiring cattle causes matrilineal Bantu–speaking societies to shift to patrilineal or mixed descent, examined the temporal order of cattle acquisition and matriliny loss, and discussed why matriliny associates with horticulture rather than pastoralism. The authors employed a phylogenetic comparative method with a maximum–parsimony Bantu language tree to test for coevolution between cattle acquisition and descent patterns, and they proposed a daughter–biased parental investment hypothesis supported by sex, wealth, and reproductive success data from the Chewa and Gabbra societies. The results confirm that cattle acquisition caused formerly matrilineal Bantu–speaking cultures to shift to patrilineal or mixed descent, and they support a daughter–biased parental investment hypothesis explaining matriliny’s rarity in pastoralist societies.

Abstract

Matrilineal descent is rare in human societies that keep large livestock. However, this negative correlation does not provide reliable evidence that livestock and descent rules are functionally related, because human cultures are not statistically independent owing to their historical relationships (Galton's problem). We tested the hypothesis that when matrilineal cultures acquire cattle they become patrilineal using a sample of 68 Bantu– and Bantoid–speaking populations from sub–Saharan Africa. We used a phylogenetic comparative method to control for Galton's problem, and a maximum–parsimony Bantu language tree as a model of population history. We tested for coevolution between cattle and descent. We also tested the direction of cultural evolution––were cattle acquired before matriliny was lost? The results support the hypothesis that acquiring cattle led formerly matrilineal Bantu–speaking cultures to change to patrilineal or mixed descent. We discuss possible reasons for matriliny's association with horticulture and its rarity in pastoralist societies. We outline the daughter–biased parental investment hypothesis for matriliny, which is supported by data on sex, wealth and reproductive success from two African societies, the matrilineal Chewa in Malawi and the patrilineal Gabbra in Kenya.