Male Violence and Sexual Intimidation in a Wild Primate Society

Abstract

Sexual violence occurring in the context of long-term heterosexual relationships, such as sexual intimidation, is widespread across human populations [1-3]. However, its evolutionary origins remain speculative because few studies have investigated the existence of comparable forms of sexual coercion in animals [4, 5], in which repeated male aggression toward a female provides the aggressor with delayed mating benefits [6]. Here, we test whether male aggression toward females functions as sexual coercion in wild chacma baboons (Papio ursinus). We found support for all three main predictions of the sexual coercion hypothesis [7]: male aggression (1) is greatest against cycling females, (2) is costly and represents the main source of injuries for cycling females, and (3) increases male mating success with their victims in the future. Detailed analysis of chronological sequences between aggression and matings ruled out other coercive mechanisms, such as short-term harassment and punishment, by showing that aggression and matings are temporally decoupled. This decoupling may explain why some forms of sexual violence have been largely overlooked in well-studied animal populations despite their likely impact on the fitness of both sexes. Finally, we found no support for alternative hypotheses such as a female preference for aggressive males [8, 9]. This new, detailed study of the forms and intensity of sexual intimidation in a wild primate suggests that it may be widespread across mammalian societies, with important implications for understanding the evolution of mate choice and sexual conflict in mammals, as well as the origins of human sexual violence.

Baboon thanatology: responses of filial and non-filial group members to infants' corpses

“…Detailed observations of troop members' responses to the corpse of an infant baboon following the loss of her mother (who died 2 days before her infant). 15 July 2017 1720: CYS carries the corpse in his mouth by its tail. 1740: CYS carries the corpse by holding it to his ventrum up and onto the sleeping cliff.…”

Having a Daughter Reduces Male Violence Against a Partner

“…IPV is observed in not only humans, but also other species; similar behaviors have recently been observed among baboons(Baniel et al, 2017) and chimpanzees(Feldblum et al, 2014), leading biologists to speculate on the genetic and evolutionary origins of IPV. 2 I exclude Asian countries (Afghanistan, Myanmar, India, Jordan, Nepal, and Pakistan) given the literature emphasizing strong son preferences in these countries and unbalanced sex ratios even at first birth (for example, according to the latest DHS survey done in Afghanistan only 42 percent of the firstborn children are girls, which raises doubts about the randomness of the sex of the reported firstborn).…”

Friend or foe: reconciliation between males and females in wild chacma baboons

“…Damaged relationships with males may also result in females losing males' protection, and potentially incurring subsequent harassment from dominant females and aggression from other resident males (Lemasson, Palombit, & Jubin, 2008;Nguyen, Van Horn, Alberts, & Altmann, 2009), and of associated costs such as injuries (Baniel et al, 2017) and increased risks of miscarriages (Zipple et al, 2017). Friendships with males also buffer females against elevated stress levels during periods of group instability, such as when a new male immigrates (e.g., Beehner, Bergman, Cheney, Seyfarth, & Whitten, 2005).…”

“…Research on reconciliation in chacma baboons to date may reflect this imbalance, focusing exclusively on post-conflict behaviour amongst adult female opponents (e.g., Cheney et al 1995;Silk et al 1996;Wittig et al 2007). It is therefore of interest to investigate whether heterosexual opponent dyads also reconcile, particularly given the high frequency of male aggression towards females in this species (Baniel, Cowlishaw, & Huchard, 2017). The presence of reconciliation between males and females would further elucidate the nature and value of adult heterosexual bonds in promiscuous societies, including how those bonds are sustained despite conflict being a common occurrence.…”