In a groundbreaking study that challenges long-held assumptions about gender dynamics in the animal kingdom, researchers from the Max Planck Institute for Evolutionary Anthropology and the University of Turku reveal that female mountain gorillas hold significant social power over males, even in the face of pronounced sexual dimorphism. Traditionally, male gorillas have been viewed as the dominant sex due to their greater body size and strength, but this comprehensive investigation into three decades of behavioral data in wild populations turns this idea on its head, offering a new lens through which to view intersexual power relations in primates.
Mountain gorillas (Gorilla beringei beringei), native to the dense forests of Bwindi Impenetrable National Park in Uganda, exhibit some of the most extreme examples of sexual dimorphism among great apes. Males weigh roughly twice as much as females and possess a thoracic and cranial morphology conducive to dominance in physical confrontations. Canine teeth size also favors males, historically interpreted as an unambiguous indicator that males maintain social supremacy over females. However, this new research undermines such deterministic views by revealing that females can and do assert dominance over males within their social groups.
Through meticulous analysis of behavioral interactions recorded over thirty years across four distinct social groups of mountain gorillas, the authors observed that females overpower at least one male in nearly every multi-male group examined. Remarkably, despite their much smaller body mass, females prevailed in one out of every four conflict encounters and specifically outranked one-quarter of non-alpha males in social hierarchies. This finding is particularly striking considering that previous assumptions favored the alpha male’s dominance as nearly absolute within these communities.
Several hypotheses have been proposed to explain how females achieve this relative ascendancy despite their size disadvantage. One possibility is that alpha males, who hold the top rank within their groups, may tacitly or actively support females against subordinate males. This alliance could serve the alpha male’s interests by facilitating group cohesion or maintaining control over reproductive opportunities. Alternatively, non-alpha males might defer to females as a strategy to avoid expulsion from winning coalitions, signaling a more complex negotiation of social power than mere brute force.
Beyond dominance interactions, the study reveals that female gorillas enjoy priority access to valuable food resources over the males they outrank. This overturns the traditional narrative that males and females segregate competition domains—where females vie for nutritional resources and males for mating privileges—and instead suggests direct competition across both domains. Such findings compel a revision of the basic frameworks that have long governed interpretations of sexual selection and resource competition in primates.
From a mechanistic perspective, the observations defy the simplistic correlation between size and social power. Despite adult females being significantly smaller and physically weaker than many males—especially those neither young nor old—females routinely outrank these males in dominance hierarchies. This insight implies that alternative mechanisms contribute to female social power, potentially including social alliances, behavioral strategies, reproductive choices, and cognitive skills involved in conflict resolution and hierarchy negotiation.
These data add to an emerging paradigm that views intersexual power not as a dichotomy but rather a continuum ranging from strict male dominance to female-biased power structures. Other primates exemplify this variation: bonobos exhibit female dominance, chimpanzees typically demonstrate male dominance, and gorillas reveal a more nuanced and flexible arrangement that defies strict categorization. By situating gorillas along this spectrum, the study enriches our understanding of the ecological and evolutionary factors that shape power dynamics across taxa.
Importantly, this research also holds profound implications for anthropological discourse concerning the nature of patriarchy in human societies. If gorillas—our close evolutionary cousins with pronounced sexual dimorphism—display such complex and, at times, female-favored social structures, it suggests that human patriarchy is less a biological inevitability rooted in primate ancestry and more a cultural construct shaped by sociopolitical factors. The study thus encourages a reconsideration of how gender power relations might be understood through an evolutionary lens that accounts for flexibility and contingency.
Furthermore, female gorillas’ ability to choose mating partners, an indicator tied closely to reproductive autonomy, supports the contention that female agency plays a critical role in these dynamics. Such selective pressures may drive the evolution of traits facilitating negotiation and influence beyond mere physical confrontation. This behavioral strategy underscores the importance of cognitive and social competencies that females harness to navigate complex social landscapes effectively.
The research also underscores the importance of longitudinal field studies for unraveling the intricate social fabric of wild animal populations. The extensive dataset accumulated over decades allowed the authors to observe consistent patterns and exceptions that short-term studies might easily overlook. Such comprehensive data provide a rare window into the subtle interactions and strategies that govern group living and survival.
In revealing that female mountain gorillas can outrank non-alpha males and access preferred resources, this work contributes significantly to ethology, evolutionary biology, and primatology by expanding our conceptual framework. It challenges the assumptions underlying sexual selection theories that privilege size and strength as the primary determinants of power, highlighting instead a multifaceted and context-dependent spectrum of dominance.
Ultimately, this study not only reshapes the narrative of gorilla social structure but also prompts a reevaluation of how dominance and power manifest across species, including our own. It invites scientists and the public alike to appreciate the complexity of gender relations in nature and consider alternative pathways to social organization that transcend traditional gendered binaries.
As ongoing research continues to probe the biological and sociocultural determinants of power dynamics, the findings from gorilla populations offer a clarion call to embrace nuance and diversity in understanding social hierarchies. This awareness holds the potential to enrich discussions on gender, evolution, and society across scientific disciplines.
Subject of Research: Female dominance and social power dynamics in mountain gorillas (Gorilla beringei beringei)
Article Title: Female mountain gorillas can outrank non-alpha males
News Publication Date: August 7, 2025
Web References: http://dx.doi.org/10.1016/j.cub.2025.07.006
Image Credits: © Martha Robbins
Keywords: sexual dimorphism, social dominance, female power, mountain gorillas, primate behavior, intersexual competition, sexual selection, evolutionary anthropology, social hierarchy
