biostudies-literatureTorres-Tamayo NLeverhulme TrustLeakey FoundationGreat Britain Sasakawa FoundationEuropean CommissionPrimate Research Institute, Kyoto University (Cooperative Research Program)Division of Behavioral and Cognitive Sciencese25064https://www.ebi.ac.uk/biostudies/studies/S-EPMC11799747biostudies-literatureUnknown186(2)<h4>Objectives</h4>The unfused human pubic symphysis has been interpreted as an obstetric adaptation to facilitate the passage of a large-brained baby through a relatively small, bipedally adapted pelvis. The degree of fusion of the adult pubic symphysis was evaluated across primate species to gauge whether an open symphysis can be interpreted as an obstetric adaptation in humans and other primates.<h4>Materials and methods</h4>Symphyseal fusion was assessed in 718 individuals from 67 nonhuman primate species. Variation in fusion in specimens of known ages and sex from four species (Galago moholi, Macaca mulatta, Microcebus murinus, and Pan troglodytes) was further examined, with detailed analyses of pubic changes by age and sex carried out through logistic regressions in macaques.<h4>ResuAmerican journal of biological anthropologyVariation in Pubic Symphysis Fusion Across Primates: Implications for Obstetric Adaptation.PMC117997471720128B1301623366RPG-2021-130BE-TAF-8273AT-TAF-8623FR-TAF-8393Hirasaki ETorres-Tamayo NBuck LTRae TCBetti LfalseVariation in Pubic Symphysis Fusion Across Primates: Implications for Obstetric Adaptation.<h4>Objectives</h4>The unfused human pubic symphysis has been interpreted as an obstetric adaptation to facilitate the passage of a large-brained baby through a relatively small, bipedally adapted pelvis. The degree of fusion of the adult pubic symphysis was evaluated across primate species to gauge whether an open symphysis can be interpreted as an obstetric adaptation in humans and other primates.<h4>Materials and methods</h4>Symphyseal fusion was assessed in 718 individuals from 67 nonhuman primate species. Variation in fusion in specimens of known ages and sex from four species (Galago moholi, Macaca mulatta, Microcebus murinus, and Pan troglodytes) was further examined, with detailed analyses of pubic changes by age and sex carried out through logistic regressions in macaques.<h4>Resu2025-01-01T00:00:00Z2025 Feb2025-04-04T01:37:17.389Z2025-04-04T01:37:17.389ZS-EPMC117997473991085710.1002/ajpa.25064