Respect for males amid suppression of females: Selective use of aggression and fitness correlates in the male-dominated society of hamadryas baboons

Katarina D Evans; Larissa Swedell; Shahrina Chowdhury

doi:10.1016/j.jhevol.2022.103151

Respect for males amid suppression of females: Selective use of aggression and fitness correlates in the male-dominated society of hamadryas baboons

J Hum Evol. 2022 Apr:165:103151. doi: 10.1016/j.jhevol.2022.103151. Epub 2022 Feb 24.

Authors

Katarina D Evans¹, Larissa Swedell², Shahrina Chowdhury³

Affiliations

¹ Anthropology Program, Graduate Center, City University of New York, 365 5th Ave, New York, NY, 10016, USA; The New York Consortium in Evolutionary Primatology, New York, NY, 10016, USA. Electronic address: kevans@gradcenter.cuny.edu.
² Anthropology Program, Graduate Center, City University of New York, 365 5th Ave, New York, NY, 10016, USA; The New York Consortium in Evolutionary Primatology, New York, NY, 10016, USA; Anthropology Department, Queens College, City University of New York, 65-30 Kissena Blvd, Flushing, NY, 11367, USA; Archaeology Department, University of Cape Town, Rondebosch, Western Cape, 7700, South Africa.
³ Anthropology Program, Graduate Center, City University of New York, 365 5th Ave, New York, NY, 10016, USA; The New York Consortium in Evolutionary Primatology, New York, NY, 10016, USA; Anthropology Department, Brooklyn College, City University of New York, 2900 Bedford Ave, Brooklyn, NY, 11210, USA.

PMID: 35219955
DOI: 10.1016/j.jhevol.2022.103151

Abstract

Hamadryas baboons (Papio hamadryas) are a useful model for human social evolution for multiple reasons, including their multilevel society, intense cross-sex bonds, and intermale tolerance. Their most stable social grouping, the one-male unit (OMU)-comprising a leader male, females, and sometimes follower males-is formed via successive takeovers of individual females by males. While takeovers occur via both aggressive and non-aggressive mechanisms, aggressive herding is common during and after takeovers and appears crucial in maintaining OMUs. Here we use behavioral and demographic data from Filoha, Ethiopia to examine the relationship between aggressive takeovers and fitness correlates. We found no relationship between a male's percentage of takeovers that were aggressive and his presumed number of infants sired, nor his number of females or followers. However, we did find that a leader male's average intensity of aggression toward both other males and females around the time of a takeover was negatively related to his presumed number of infants sired. In addition, a leader male's average intensity of aggression toward other males was negatively related to his maximum number of followers. Finally, leader males exhibited more intense aggression toward females in interband, compared to intraband, takeovers. Our findings suggest that (1) leader males who limit their aggression toward other males may have greater success in attracting followers, thereby increasing their fitness via enhanced defense of the OMU; (2) exceptionally aggressive takeovers may lead to lower birth rates via female reproductive suppression; and (3) the extent to which males use aggression toward females depends on the context in which the takeover occurs. Overall, these results both suggest that hamadryas males use aggression selectively and underscore the ubiquity of intermale tolerance and female suppression in the hamadryas social system. This study lends insight into the interplay between male-female and male-male social dynamics during human evolution.

Keywords: Coercion; Fitness; Male aggression; Reproductive strategies; Reproductive success; Sexual conflict.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aggression
Animals
Female
Humans
Male
Papio hamadryas*
Reproduction
Sexual Behavior, Animal*
Social Behavior