A comparative network approach to assess the social-ecological underpinnings of zoonotic outbreaks at human-wildlife interfaces

Pandemics caused by wildlife-origin pathogens, like COVID-19, highlight the importance of understanding the ecology of zoonosis at human-wildlife interfaces. To-date, the relative effects of human-wildlife and wildlife-wildlife interactions on zoonotic outbreaks among wildlife populations remain unclear. In this study, we used social network analysis and epidemiological Susceptible Infected Recovered (SIR) models, to track zoonotic outbreaks through wild animals social-ecological co-interactions with humans and their social grooming interactions with conspecifics, for 10 groups of macaques (Macaca spp.) living in (peri)urban environments across Asia. Outbreak sizes predicted by the SIR models were related to structural features of the social networks, and particular properties of individual animals connectivity within those networks. Outbreak sizes were larger when the first-infected animal was highly central, in both types of networks. Across host-species, particularly for rhesus and bonnet macaques, the effects of network centrality on outbreak sizes were stronger through macaques human co-interaction networks compared to grooming networks. Our findings, independent of pathogen-transmissibility, suggest that for wildlife populations in the Anthropocene, vulnerability to zoonotic outbreaks may outweigh the potential/perceived benefits of interacting with humans to procure anthropogenic food. From One Health perspectives, animals that consistently interact with humans (and their own conspecifics) across time and space are useful targets for disease-control.

Infant Survival Among Free-Living Bonnet Macaques (Macaca radiata) in South India

Female reproductive success depends to a large extent on infants’ ability to survive to maturity. While most studies of female reproductive success have focused on the effects of individuals’ sociodemographic factors (e.g., age/parity, dominance rank) on offspring survival among wild primates living in less disturbed habitats, little research has focused on offspring survival in urban or periurban animals. Here we investigated sociodemographic and anthropogenic determinants of infant survival (up to 1 yr of age) in free-ranging bonnet macaques (Macaca radiata) living in a periurban environment in Southern India. We conducted the study from November 2016 to May 2018, on two groups of bonnet macaques at the Thenmala tourist site in the state of Kerala. Fifty infants were born across two birth seasons. Of these infants, 29.2% died or disappeared in 2017 and 26.9% died or disappeared in 2018. We found that infant survival was strongly influenced by the mother’s parity: infants of experienced mothers had a better chance of survival than those of first-time mothers. We also found that male infants were more likely to die than female infants. However, we found no effects of mothers’ dominance rank, or of frequency of mothers’ interactions with humans and time spent foraging on anthropogenic food, on infant survival. Our results, consistent with findings from other wild primate species, show that even in challenging human-impacted environments, experienced bonnet macaque mothers have greater success than inexperienced ones.

Impact of individual demographic and social factors on human–wildlife interactions: a comparative study of three macaque species

Despite increasing conflict at human–wildlife interfaces, there exists little research on how the attributes and behavior of individual wild animals may influence human–wildlife interactions. Adopting a comparative approach, we examined the impact of animals’ life-history and social attributes on interactions between humans and (peri)urban macaques in Asia. For 10 groups of rhesus, long-tailed, and bonnet macaques, we collected social behavior, spatial data, and human–interaction data for 11–20 months on pre-identified individuals. Mixed-model analysis revealed that, across all species, males and spatially peripheral individuals interacted with humans the most, and that high-ranking individuals initiated more interactions with humans than low-rankers. Among bonnet macaques, but not rhesus or long-tailed macaques, individuals who were more well-connected in their grooming network interacted more frequently with humans than less well-connected individuals. From an evolutionary perspective, our results suggest that individuals incurring lower costs related to their life-history (males) and resource-access (high rank; strong social connections within a socially tolerant macaque species), but also higher costs on account of compromising the advantages of being in the core of their group (spatial periphery), are the most likely to take risks by interacting with humans in anthropogenic environments. From a conservation perspective, evaluating individual behavior will better inform efforts to minimize conflict-related costs and zoonotic-risk.

Gestural Communication of Wild Bonnet Macaques in the Bandipur National Park, Southern India

Nonhuman primate gestures are believed to be crucial evolutionary precursors of human language. Comparative studies on primate gestures in an evolutionary framework have, however, remained largely restricted to the great apes and the potential flexibility and richness of gestural communication in monkeys, especially in the wild, continue to be virtually unknown. In this paper, we followed several criteria, adapted from ape gesture studies, to identify gestures and evaluate their contexts of usage in the repertoire of wild bonnet macaques Macaca radiata in the Bandipur National Park of southern India. This report is the first of its kind to systematically identify gestures in any wild, non-ape species, thus providing a platform for comparative studies across primate taxa, particularly in our efforts to trace out the phylogenetic origins of language-like markers in the primate lineage, earlier than in the great apes.