Gibraltar Macaques Project
Jeanne Thiodet (2025). Impact of Anthropogenic Pressure on the Behaviour of Barbary Macaques (Macaca sylvanus) in Gibraltar. Master Thesis, University Paris Sorbonne Nord
Abstract: Wildlife tourism is an increasingly widespread practice throughout the world. Primates are particularly popular with visitors because of their behavioural and physiological proximity to humans. In this study, we investigate the impact of anthropogenic pressure from visitors on the behaviour of Barbary macaques (Macaca sylvanus) in the Upper Rock Nature Reserve in Gibraltar. We collected data for 2 months from January to March 2025, on the number of tourists, vehicles, human-macaque interactions and noise intensity in 10 different sites, and on the impact of these anthropogenic pressures on the behaviour of 47 individuals (self-centred behaviour, agonistic behaviour and affiliative behaviour). The results showed a heterogeneous spatialisation of anthropogenic pressure according to the different sites. We showed a negative association between the number of visitors and the number of yawns, and a positive association between the number of vehicles and the number of yawns, as well as a positive associative trend between self-scratching and the number of visitors. These results suggest that certain self-directed behaviours, such as yawning and self-scratching, may be sensitive to specific indicators of anthropogenic pressure, while affiliative and agonistic behaviours appear to be less directly affected, highlighting a possible modulation linked to other factors (hierarchy, intra-group pressure, etc.). By highlighting the diversity of behavioural responses to gradients in tourist numbers, this study highlights the need for differentiated management of sites according to their level of exposure, in order to preserve the well-being of the macaques and promote sustainable cohabitation with visitors.
Eliott Mestrallet (2025). Behavioural Adaptations and Tourist-Macaque Interactions: A Comparative Study of Social Learning in Gibraltar's Barbary Macaques Master Thesis, University Paris Saclay, University of Cambridge
Abstract: In Gibraltar's Upper Rock Nature Reserve, Barbary macaques (Macaca sylvanus) are daily exposed to high levels of human presence, particularly through tourism. This study investigates how macaques from four social groups navigate such anthropogenic pressure, combining systematic observational data with a controlled problem-solving task. Behavioural observations were collected using a structured location sampling protocol, revealing group-level differences in interaction rates, food-related behaviours, and pillaging tendencies. Groups situated near high-density tourist areas showed more frequent and prolonged interactions, especially when food was involved. An experimental task using a transparent pencil case filled with peanuts allowed for individual-level assessment of cognitive engagement. Results showed considerable variability in task interaction and success, which could not be explained by group origin or sex. Instead, behavioural indicators of stress, emerged as reliable predictors of problem-solving efficiency, with higher stress associated with longer latencies to success. These findings highlight the behavioural plasticity of Barbary macaques in human-modified environments, as well as the role of emotional state and social context in shaping their responses. Rather than displaying uniform strategies, individuals and groups differ in how they approach human artefacts and manage cognitive challenges. This study contributes to our understanding of primate adaptability in anthropogenic landscapes and underscores the need to account for emotional and ecological variables in conservation and wildlife management strategies.
Rosalind Wippell (2025). POPULATION SCALE AND INTER-INDIVIDUAL, SPATIAL PROXIMITY VARIATION IN BARBARY MACAQUES (MACACA SYLVANUS). Undergraduate dissertation, Archaeology Department, University of Cambridge
Abstract:
Proximity may be used as a proxy when investigating social relationships between primates. Using social network analysis and generalised linear mixed models, this study investigated the variation in inter-individual proximity in five groups of Barbary macaques (Macaca sylvanus) and whether this was influenced by seasonality, grooming and rank differences in the groups. This has not previously been explored in Gibraltar.
This study found that grooming and proximity were associated in most groups, indicating that those in closer proximity were more likely to groom. In some groups, male-male dyads were shown to be more spread than female-female dyads in winter compared to summer, and most groups showed males to be more spread than females overall, likely reflecting kinship between philopatric females. Rank difference had a significant effect on proximity in one group, where higher food competition may have resulted in stricter hierarchies. Group differences in spread were shown to reflect home-ranges and the importance of the anthropogenic environment in which the macaques live.
Thiodet-Barbier, J. & Lemoine, S. (2024). Extractive foraging adaptive strategies to an anthropized environment in Barbary macaques (Macaca sylvanus). 36th Meeting of the Societe Francophone de Primatology. Toulouse, France
Frater, J. & Lemoine, S. (2023). The human-primate interface of Gibraltar: relevance and potential for ethnoprimatology and evolutionary studies. Primate Society of Great Britain, Spring meeting 2023, Cambridge, UK.
