behavioral ecology of macaques – Science https://scienmag.com Wed, 22 Apr 2026 09:59:19 +0000 en-US hourly 1 https://wordpress.org/?v=7.1.1 https://scienmag.com/wp-content/uploads/2024/07/cropped-scienmag_ico-32x32.jpg behavioral ecology of macaques – Science https://scienmag.com 32 32 73899611 Monkeys Use Soil as Natural Remedy to Digest Tourists’ Junk Food, Study Finds https://scienmag.com/monkeys-use-soil-as-natural-remedy-to-digest-tourists-junk-food-study-finds/ Wed, 22 Apr 2026 09:59:19 +0000 https://scienmag.com/monkeys-use-soil-as-natural-remedy-to-digest-tourists-junk-food-study-finds/ In the rocky outcrop of Gibraltar, a unique and unexpected behavioral adaptation is unfolding among the local population of Barbary macaques. These primates, well-known for their close association with human visitors in this European enclave, have recently been observed engaging in geophagy—the deliberate consumption of soil. This phenomenon, documented extensively in a recent University of Cambridge-led study, hints at a remarkable example of how animal behavior adapts under the pressures of anthropogenic environments and human influence.

The Barbary macaques of Gibraltar represent Europe’s only free-ranging monkey population, and researchers have been meticulously monitoring their interactions with humans and their environment. Over a span of 98 observation days, it became apparent that these monkeys are increasingly consuming soil, especially during the bustling peak tourism season. The pattern strongly correlates with the macaques’ access to human-derived junk foods such as chocolate, crisps, ice cream, and bread — highly processed, calorie-dense snacks that starkly contrast with their natural diets of herbs, leaves, seeds, and insects.

Geophagy, although documented in other primates such as lemurs and chimpanzees, is notably high in these macaques, with around twelve documented soil-eating events per week, a frequency rivalling those of primates in more natural habitats. The intriguing hypothesis emerging from this research suggests that the soil consumption acts as a physiological countermeasure to the digestive disturbances caused by the unnatural, human-provided foods. These foods, rich in sugars, salts, and dairy, disrupt the macaques’ gut microbiome, leading to ailments ranging from mild gastrointestinal discomfort to more severe issues like nausea and diarrhea.

Dr. Sylvain Lemoine, the study’s lead author and a biological anthropologist at Cambridge’s Department of Archaeology, emphasizes that geophagy here serves a dual role—both functional and cultural. The soil ingestion likely helps line and protect the gastrointestinal tract, absorbing harmful compounds and providing essential minerals absent in their tourist-induced diet. More fascinatingly, this behavior appears to be socially transmitted within macaque troops, revealing an emergent cultural tradition shaped by close contact with humans.

Different macaque groups display distinctive preferences for particular types of soil, a testament to culturally embedded behaviors within these primate populations. The preference for “terra rossa,” a red clay soil prevalent in Gibraltar, dominates 83% of geophagy cases, except in one troop residing in the lower Rock slopes, which favors tar-contaminated soil found in asphalt potholes. This divergence indicates localized traditions likely passed on through social learning, much like tool use variations observed in chimpanzees.

The macaques’ inclination toward junk food supplied or inadvertently left by tourists has amplified over recent years, despite official efforts to regulate feeding. While local authorities provide fresh fruit, vegetables, and water at designated stations to maintain macaque health, the monkeys often circumvent these restrictions. In fact, nearly 19% of their overall diet recorded during the study comprised of human junk food. Moreover, those troops dwelling near the top of the Rock, where human activity is densest, consumed tourist food at rates two and a half times higher than groups in less accessible areas, prompting elevated soil consumption as a coping mechanism.

Seasonal variations in behavior reinforce this relationship between dietary stress and geophagy. Both dirt-eating and junk food consumption decline significantly in the winter months when tourist numbers, and consequently picnic leftovers and snacks, decrease. Conversely, the summer months witness heightened tourist macaque interaction, escalating the frequency of junk food intake and soil consumption in tandem.

Notably, the study underscores that geophagy in Gibraltar’s macaques is not linked to physiological states such as pregnancy or lactation, a pattern often observed in other primates, including humans, where soil-eating supplements specific nutritional needs. Instead, it is predominantly a protective behavioral adaptation against the digestive challenges imposed by the human-influenced diet.

Historical context adds depth to understanding this unique primate-human nexus. Barbary macaques are believed to have been introduced to Gibraltar during medieval Moorish rule, their presence intertwined with centuries of human history on the Rock. In World War II, concerns over maintaining morale led Winston Churchill to replenish dwindling macaque populations, further embedding these primates as symbols of human heritage and identity intertwined with the natural world.

This natural experiment—wherein Gibraltar’s primates confront a landscape transformed both ecologically and socially by humans—illuminates the dynamic ways animal cultures evolve. Geophagy here exemplifies not merely an isolated survival tactic but also a culturally transmitted tradition, forged and perpetuated by proximity and interaction with people, marking a significant milestone in documenting how anthropogenic landscapes impact primate behavior.

The study’s implications extend beyond academic interest, suggesting broader consequences for wildlife conservation and management in human-dominated habitats. Understanding how primates and, by extension, wildlife adapt to human-induced dietary shifts can inform strategies aimed at reducing negative health impacts and preserving natural behavioral repertoires against the backdrop of expanding urbanization and tourism.

Future research may focus on analyzing the precise mineralogical and microbiological properties of consumed soils, and their specific therapeutic effects on the macaques’ gut flora and overall health. Experimental approaches, including offering controlled soil samples, could unravel the cognitive and social mechanisms underpinning this cultural behavior, granting insights into primate learning, adaptation, and resilience.

In conclusion, the geophagy documented in Gibraltar’s Barbary macaques stands as a compelling paradigm of primate cultural evolution influenced directly by human activity. This intricate interplay of environment, diet, health, and social learning paints a vivid picture of adaptation in an anthropocentric era, urging continued observation and multidisciplinary inquiry to decode the complex narratives emerging at the intersection of wildlife and human society.

Subject of Research: Animals

Article Title: Geophagy in Gibraltar Barbary macaques is a primate tradition anthropogenically induced

News Publication Date: 22-Apr-2026

Web References:
10.1038/s41598-026-44607-0

Image Credits: Martin Nicourt/Gibraltar Macaques Project

Keywords: Geophagy, Barbary macaques, Gibraltar, primate behavior, anthropogenic landscapes, gut microbiome, cultural transmission, tourism impact, animal adaptation, primate tradition, soil consumption, digestive health

]]> 153311 Monkey Database Uncovers Growing Shift Toward Open Science https://scienmag.com/monkey-database-uncovers-growing-shift-toward-open-science/ Thu, 24 Apr 2025 16:35:10 +0000 https://scienmag.com/monkey-database-uncovers-growing-shift-toward-open-science/ In the rapidly evolving landscape of animal behavior research, the advent of large-scale collaborative databases is transforming the way scientists approach the complexities of social interactions within animal societies. Among these pioneering initiatives, MacaqueNet stands out as a trailblazing platform that aggregates social behavioral data from multiple species of macaques, ushering in a new era of transparency, cooperation, and data-driven discovery across the global research community.

MacaqueNet, launched in 2017, has matured into the largest publicly accessible and standardized database dedicated to animal social behavior, currently encompassing data from 14 of the world’s 24 macaque species. This expansive data repository integrates observations across 61 populations and over 3,000 individual macaques, highlighting the sheer scale and granularity of information now available to researchers interested in comparative behavioral ecology.

What differentiates MacaqueNet from traditional datasets is its structure as a cross-species, cross-population collaborative effort that encourages researchers to contribute and share their raw social data. This design fosters not only consistency in behavioral measurements but also enhances replicability and meta-analytic possibilities, which are critical for testing broad evolutionary and ecological hypotheses about sociality among primates.

At the heart of this endeavor lies the technical challenge of harmonizing data collected under varying protocols, environments, and observational conditions. The MacaqueNet team has implemented rigorous data standardization procedures, ensuring that diverse datasets are comparable and integrable. Metadata standards allow for detailed annotations on context, observer effort, and behavioral definitions, which are indispensable for minimizing biases inherent in observational behavioral research.

The repository’s accessibility is a significant stride towards an open science framework in animal behavior. All data within MacaqueNet is openly accessible or made available upon request, aligning with the principles of open data and contributing to a culture of transparency. This openness invites new analytical approaches, from network analysis to machine learning, empowering scientists to uncover complex social patterns that were previously invisible due to scattered or siloed data sources.

Delphine De Moor, a key researcher at the University of Exeter and contributor to MacaqueNet, emphasizes the paradigm shift that such collaborative platforms represent. By consolidating data from myriad researchers, institutions, and continents, MacaqueNet facilitates large-scale inquiries impossible for individual labs. This aggregation enables sophisticated analyses of interspecific variation, demographic effects, and environmental influences on social behavior patterns.

The platform does not merely serve as a passive data warehouse but actively cultivates a community of scholars united by shared standards and collaborative goals. This dynamic fosters mutual incentives for data sharing and co-authorship, catalyzing a shift away from traditional competitive paradigms towards cooperative scientific enterprise. MacaqueNet thereby models how big-team science can accelerate progress in understanding complex social systems.

Beyond its current scope, MacaqueNet is envisioned as a replicable template for other taxa and behavioral domains. Its modular, open-source architecture ensures it can be adapted to incorporate additional species or to study other facets of animal sociality, such as communication or cooperative behaviors. This scalability is critical for advancing synthetic approaches in behavioral ecology and evolutionary biology.

Notably, the project’s success is underpinned by a meticulously curated team of over 100 members distributed across 58 institutes worldwide. Such diversity in expertise and geographic representation enhances the robustness and ecological validity of the assembled data. The collaboration spans disciplines including ethology, primatology, computational biology, and data science, exemplifying interdisciplinary synergy in action.

The open accessibility of MacaqueNet’s components extends to its technical backbone, which is hosted on a publicly available repository. This transparency not only facilitates reproducibility but also invites continuous development and iterative improvement by the broader scientific community, embodying principles of collaborative software development.

For behavioral ecologists and primatologists alike, MacaqueNet provides unprecedented opportunities to address pressing scientific questions. These range from deciphering the evolutionary origins of social complexity among primates to examining the impacts of environmental changes on social networks. As data continues to accumulate, the potential for transformative discoveries grows exponentially.

Complementing the scientific infrastructure, communication efforts such as blog posts and accessible summaries help disseminate these advances beyond specialist circles, engaging the broader public and policy-makers. This elevation of behavioral research’s profile underscores the societal relevance of understanding animal social behavior in an era of rapid ecological change.

In sum, MacaqueNet represents a landmark in collaborative behavioral research, exemplifying how communal data sharing and methodological standardization can unleash new insights into the intricacies of primate social life. By pioneering an open, scalable, and integrative approach, it sets a compelling precedent for the future of animal behavior science.

Subject of Research: Animal social behaviour, comparative primatology, social networks in macaques
Article Title: MacaqueNet: Advancing comparative behavioural research through large-scale collaboration
News Publication Date: 11-Feb-2025
Web References:

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