Marriage dynamics in old Lower California: ecological constraints and reproductive value in an arid peninsular frontier

ABSTRACT

It is commonly expected that natural selection will favor earlier reproduction, yet ecological constraints can force people to delay marriage. Furthermore, humans demonstrate sex-specific preferences in marriage partners – with grooms normally a few years older than their brides; however, the age at which individuals marry can influence the spousal age gap. We investigate factors influencing age at first marriage and age difference at marriage using nineteenth-century historical demographic data from Baja California Sur, Mexico. Analyses suggest ecological constraints affected male, but not female, age at first marriage. Males who migrated from their natal community and who married in communities whose primary economic activity was agriculture experienced delayed age at first marriage. The age at which females first married increased over time causing a reduction in the age gap between spouses. Furthermore, the spousal age gap showed sex-specific effects: women who married early in life were much younger than their husbands, while women who married late in life were older than their husbands, suggesting that variation in female reproductive value influenced mate choice. Males, on the other hand, who married late in life showed a preference for marrying much younger females, indicating preferences for females with high reproductive value.

Acknowledgments

The authors thank the Center for Latin American Studies, as well as, the Undergraduate Research Opportunities Program at the University of Utah for financially supporting aspects of this research. Additionally, we thank Chris Coates, Miriam Shryver, and the students of the course ANTH 3140: “Peoples and Cultures of Latin America” during the Fall Semester 2017 for data coding. Last, we thank two anonymous reviewers for providing valuable commentary on an original version of the manuscript.

Disclosure Statement

The authors have no financial interests or benefits to declare with this research.

Supplementary Material

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