Social and sexual consequences of facial femininity in a non-human primate

Sonia Tieo; Jules Dezeure; Anna Cryer; Pascal Lepou; Marie J E Charpentier; Julien P Renoult

doi:10.1016/j.isci.2023.107901

Social and sexual consequences of facial femininity in a non-human primate

iScience. 2023 Sep 12;26(10):107901. doi: 10.1016/j.isci.2023.107901. eCollection 2023 Oct 20.

Authors

Sonia Tieo¹, Jules Dezeure², Anna Cryer², Pascal Lepou², Marie J E Charpentier³, Julien P Renoult¹

Affiliations

¹ CEFE, University Montpellier, CNRS, EPHE, IRD, Montpellier, France.
² Projet Mandrillus, Fondation Lékédi pour la Biodiversité, Bakoumba BP 52, Gabon.
³ Institut des Sciences de l'Evolution de Montpellier (ISEM), UMR5554 - University of Montpellier/CNRS/IRD/EPHE, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.

Abstract

In humans, femininity shapes women's interactions with both genders, but its influence on animals remains unknown. Using 10 years of data on a wild primate, we developed an artificial intelligence-based method to estimate facial femininity from naturalistic portraits. Our method explains up to 30% of the variance in perceived femininity in humans, competing with classical methods using standardized pictures taken under laboratory conditions. We then showed that femininity estimated on 95 female mandrills significantly correlated with various socio-sexual behaviors. Unexpectedly, less feminine female mandrills were approached and aggressed more frequently by both sexes and received more male copulations, suggesting a positive valuation of masculinity attributes rather than a perception bias. This study contributes to understand the role of femininity on animal's sociality and offers a framework for non-invasive research on visual communication in behavioral ecology.

Keywords: Artificial intelligence; Biology of gender; Ethology.