Applying social network and personality trait analyses to understanding and managing human-macaque sympatry in urban Singapore

The need to understand and manage human-primate sympatry is growing in tandem with human population expansion and urbanization across primate range countries worldwide (Humle & Hill, 2016). As behaviourally flexible species, some primates thrive in human-altered habitats by adapting to urban spaces and exploiting high-quality anthropogenic foods, but these interactions often result in property damage, economic loss, and health and safety concerns for human communities and pave the way for conflict (Lee & Priston, 2005). Efforts to mitigate conflict such as culling and sterilisation are often implemented with lethal and long-term consequences for the health of wild populations, without effectively resolving conflict. In contrast, non-lethal approaches have the potential to provide ecologically sustainable solutions for managing coexistence (Treves & Naughton-Treves, 2005), but require a sound understanding of how primates acquire and transmit behavioural practices.

It is well-established that social networks in group-living primates influence the acquisition and transmission of a wide range of behavioural adaptations ranging from resource selection to tool use (Claidiere et al. 2013; Hobaiter et al. 2014; King et al. 2011; Price et al. 2017; Tan et al. 2018). There is also growing recognition that individual variation in personality traits such as boldness, anxiety, and exploratory tendency not only influence how animals adapt to urban environments (Sih et al., 2004), but further modulate social networks (McCowan et al. 2011) and how individuals generate or use information, whether asocial or socially (Carter et al., 2014; Hopper et al. 2014; Rawlings et al. 2017). These behavioural principles are thus germane to understanding the propagation of conflict-promoting behaviour within primate groups and are crucial for predicting group and individual level responses to management interventions, and yet, have rarely been applied to examining and managing human-primate interfaces (but see Donald et al. 2012 and Blackwell et al. 2016 for applications in cetaceans and carnivores). In this project we aim to address these issues within the context of human-macaque conflict in Singapore, by examining how macaque social networks and individual-specific traits can be used to understand how ‘undesirable’ behaviour is acquired and maintained in social groups and to anticipate the outcomes of conflict-mitigation strategies.

Managing human-macaque conflict has been an enduring challenge in urban Singapore. Singapore’s macaque population, estimated at approximately 2000 individuals across 92 groups, is concentrated along the edges of conserved forest fragments (Riley, Srikantan, & Gumert, 2015). In land-scarce and population-dense Singapore, these nature reserves are encircled by urban infrastructure and residential development with no buffer between macaque ranges and human settlement. Conflicts arise over macaques entering properties, raiding refuse, and snatching food. Such behaviour has been conditioned over a long history of human provisioning either via deliberate feeding, or failure by residents and park visitors to secure properties and refuse sites (Sha, Lee, Jones-Engle, & Fuentes, 2009). Historically, culling in response to complaints have resulted in up to a third of the population being exterminated in a single year (Feng, 2015). More recently however, volunteer-led organisations have initiated behavioral intervention strategies aimed at reconditioning macaque behaviour by training ‘Monkey Gaurds’ to deter macaques from entering residential premises (Figure 1), and call for accompanying research to examine and inform the efficacy of these measures.

The successful candidate will carry out field work in Singapore. They will work closely with supervisors and the Long-Tailed Macaque Working Group in Singapore (see End-User Collaboration Contributions) to identify and study groups of long-tailed macaques in problematic interface zones and to examine how macaque social networks influence patterns of anthropogenic resource use and problematic interactions with humans. Moreover, they will investigate how individual-specific traits modulate these patterns of macaque-human interactions, and how networks and individuals respond to behavioural intervention strategies.

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Image Captions

Figure 1. A news report on ‘monkey guarding’ initiatives being developed by volunteer-led organisations, to mitigate human-macaque conflict around residential estates bordering nature reserves in Singapore [image sourced from The Straits Times, October 23, 2014]


Field methods of data collection will include:
• systematic behavioural sampling (Altmann, 1974) to operationalize and quantify macaques’ anthropogenic resource use, interactions with humans, and responses to behavioural interventions, and to measure the frequencies of affiliative and agonistic interactions for constructing social networks and dominance hierarchies
• experimental behavioural assays (Carter et al. 2012a,b) involving presentation of a variety of stimuli to characterise personality traits of individual monkeys, as a complement to behavioural observations
Data analyses will involve:
• factor analysis to validate personality dimensions of individual macaques.
• Social Network Analyses (Sueur et al. 2011) to visualize and compare affiliative social networks, with associations during anthropogenic resource use events (e.g. encroachment into human settlements), and identify individuals’ roles in influencing network behaviour.
• Network Based Diffusion Analysis (Kendal et al. 2010, 2015) will be applied to tracking the spread of responses (throughout groups) to behavioural interventions. Individual demographic and personality factors will be included in the models to determine the influence of these parameters on anthropogenic resource use by individuals within groups, and how networks respond to behavioural intervention.

Project Timeline

Year 1

This is a 3.5 year studentship with a likely start date of October 2023 and completion by end March 2027.
October 2023 – April 2024 (6 months):
• Initial PhD training – thorough literature review, practice behavioural observation and transcription with existing video data, training in social network analysis.
• Pilot work in Singapore (December 2023) to survey sites, select study groups, and discuss program implementation with the Long-Tailed Macaque Working Group (MWG).
May 2024 – September 2024 (6 months):
• Detailed study design, including behavioural sampling protocols.
• Progression viva (by July 2024)
• Finalise Singapore research permits

Year 2

October 2024 – April 2025 (6 months):
• Data collection towards Objective 1 – Learning identities of individuals in study groups, social network data collection and personality testing.
May 2025 – September 2025 (6 months)
• Data collection towards Objective 2 – Measuring responses to ongoing behavioural intervention programmes (i.e. Monkey Guarding), in collaboration with MWG

Year 3

October 2025 – April 2026 (6 months):
• Data collection towards Objective 2 (continued) – Designing, implementing, and examining responses to new behavioural interventions (e.g. sensory deterrents), conceived in close collaboration with MWG
May 2026 – September 2026 (6 months):
• Data analyses
• Dissemination of information to end users
• Prepare manuscripts for submission to peer reviewed journals.

Year 3.5

October 2026 – March 2027 (6 months): Final thesis preparation and examination.

& Skills

This project provides the opportunity for a student to gain training and experience in a range of field and analytical skills, while contributing to addressing a timely real-world problem. Research experience will include field primatology (behavioural observation, experimental design), as well as behavioural transcription, statistical, and social network analyses using a variety of software (BORIS, UCINET, R). Transferrable skills include project and time management, as well as interpersonal communication, written, and oral presentation skills through both stakeholder engagement and outreach, and academic writing and conference presentations.

The supervisors have overlapping interests and expertise enabling training in all aspects necessary for this innovative project (Tan: local expertise, species expertise, primate behavioural sampling, social learning; Price: human-animal interactions, social dynamics, cultural transmission, primate behaviour; Kendal: social network analysis; cultural transmission; primate personality). Moreover, the student will benefit from the vibrant research groups of each supervisor, as well as the broader research environment and support provided by the Behavioural Ecology and Evolution Research (BEER) Centre, Primatology Group and Durham Cultural Evolution Research Centre (DCERC), and newly established Durham Research Methods centre at Durham University. In addition the Centre for Behaviour and Evolution at Newcastle University provides a supportive, interdisciplinary environment with weekly lectures and opportunities for postgraduate students to present their work at key stages.

References & further reading

Altmann, J. (1974). Observational study of behaviour: sampling methods. Behaviour, 49, 227-267.
Blackwell, B. F., DeVault, T. L., Fernández-Juricic, E., Gese, E. M., Gilbert-Norton, L., Breck, S. W. (2016). No single solution: application of behavioural principles in mitigating human-wildlife conflict. Animal Behaviour, 120, 245-254.
Carter, A. J., Marshall, H. H., Heinsohn, R., Cowlishaw, G. (2012). How not to measure boldness: novel object and anti-predator responses are not the same in wild baboons. Animal Behaviour, 84(3), 603-609.
Carter, A.J., Feeney, W. E., Marshall, H.H., & Cowlishaw, G. (2013). Evaluating animal personalities: do observer assessments and experimental tests measure the same thing? Biological Reviews, 88(2), 465-475.
Carter, A. J., Marshall, H. H., Heinsohn, R, & Cowlishaw, G. (2014). Personality predicts the propensity for social learning in a wild primate. PeerJ, 2, e283.
Claidiere, N., Messer, E. J. E., Hoppitt, W., Whiten, A. (2013). Diffusion dynamics of socially learned foraging techniques in squirrel monkeys. Current Biology, 23(13), 1251-1255.
Feng Z (2015, April 16) To cull or not to cull pesky monkeys. Retrieved from https://www.straitstimes.com/opinion/to-cull-or-not-to-cull-pesky-monkeys
Hobaiter, C., Poisot, T, Zuberbühler, K, Hoppitt, W, & Gruber, T. (2014). Social network analysis shows direct evidence for social transmission of tool use in wild chimpanzees. PLoS Biology, 12(9), e1001960.
Hopper LM, Price SA, Freeman HD, Lambeth SP, Schapiro SJ, Kendal RL. (2014). Influence of personality, age, sex, and oestrus state on chimpanzee problem-solving success. Animal Cognition 17, 835-847.
Humle, T., & Hill, C. (2016). People-primate interactions: implications for primate conservation. In S.A. Wich, & A. J. Marshall, An Introduction to Primate Conservation. Oxford: Oxford University Press.
King, A. J., Clark, F. E., Cowlishaw, G. (2011). The dining etiquette of desert baboons: the roles of social bonds, kinship, and dominance in co-feeding networks. American Journal of Primatology, 73(8), 768-774.
Kendal, R.L., Custance, D., Kendal, J.R., Vale, G., Stoinski, T., Rakotomalala, N.I. & Rasaminanana, H. (2010). Evidence for social learning in wild lemurs (Lemur catta). Learning & Behavior 38, 220-234.
Kendal, RL, Hopper, LM, Whiten, A, Brosnan, SF, Lambeth, SP, Schapiro, SJ & Hoppitt, W (2015). Chimpanzees copy dominant and knowledgeable individuals: Implications for cultural diversity. Evolution and Human Behavior 15, 65-72.
Lee, P. C., & Priston, N. E. C. (2005). Human attitudes to primates: perceptions of pests, conflict and consequences for conservation. In: Paterson, J. D. (ed), Commensalism and Conflict: The Primate-Human Interface. Norman, OK: American Society of Primatology.
McCowan, B., Beisner, B. A, Capitanio, J. P., … Fushing, H. (2011). Network stability is a balancing act of personality, power, and conflict dynamics in rhesus macaque societies. PLoSONE, 6(8), e0022530
Price, E. E., Wood, L. A., & Whiten, A. (2017). Adaptive cultural transmission biases in children and nonhuman primates. Infant Behavior and Development, 48, 45-53.
Quirin, C. & Dixon, A. (2012). Food security, politics and perceptions of wildlife damaged in Western Ethiopia. International Journal of Pest Management, 58, 101-114.
Riley CM, Jayasri SL, Gumert MD (2015) Results of a nationwide census of the long-tailed macaque (Macaca fascicularis) population of Singapore. Raffles Bulletin of Zoology, 63: 503-515.
Rawlings B, Flynn EG, Kendal RL. (2017). To copy or to innovate? The role of personality and social networks in children’s learning strategies. Child Development Perspectives 11, 39-44.
Sha JCM, Gumert MD, Lee BYP-H, Jones-Engel L, Chan S, Fuentes A (2009) Macaque-human interactions and the societal perceptions of macaques in Singapore. American Journal of Primatology, 71(10): 825-839.
Sih, A., Bell, A., & Johnson, J.C. (2004). Behavioural syndromes: An ecological and evolutionary overview. Trends in Ecology and Evolution, 19, 372-378.
Sueur, C, Jacobs, A, Amblard, F, Petit, O, & King, A. J. (2011). How can social network analysis improve the study of primate behaviour? American Journal of Primatology, 73, 703-719.
Tan, A. W., Hemelrijk, C. K., Malaivijitnond, S., & Gumert, M. D. (2018). Young macaques (Macaca fascicularis) preferentially bias attention towards closer, older, and better tool users. Animal cognition, 21(4), 551-563.

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