The Habituation Process in Two Groups of Wild Moor Macaques (Macaca maura)

When studying animal behavior in the wild, some behaviors may require observation from a relatively short distance. In these cases, habituation is commonly used to ensure that animals do not perceive researchers as a direct threat and do not alter their behavior in their presence. However, habituation can have significant effects on the welfare and conservation of the animals. Studying how nonhuman primates react to the process of habituation can help to identify the factors that affect habituation and implement habituation protocols that allow other researchers to speed up the process while maintaining high standards of health and safety for both animals and researchers. In this study, we systematically described the habituation of two groups of wild moor macaques (Macaca maura), an Endangered endemic species of Sulawesi Island (Indonesia), to assess the factors that facilitate habituation and reduce impact on animal behavior during this process. During 7 months, we conducted behavioral observations for more than 7,872 encounters and an average of 120 days to monitor how macaque behavior toward researchers changed through time in the two groups under different conditions. We found that both study groups (N = 56, N = 41) became more tolerant to the presence of researchers during the course of the habituation, with occurrence of neutral group responses increasing, and minimum distance to researchers and occurrence of fearful group responses decreasing through time. These changes in behavior were predominant when macaques were in trees, with better visibility conditions, when researchers maintained a longer minimum distance to macaques and, unexpectedly, by the presence of more than one researcher. By identifying these factors, we contribute to designing habituation protocols that decrease the likelihood of fearful responses and might reduce the stress experienced during this process.

Reaction to Snakes in Wild Moor Macaques (Macaca maura)

Snake predation is considered an important evolutionary force for primates. Yet, very few studies have documented encounters between primates and snakes in the wild. Here, we provide a preliminary account of how wild moor macaques (Macaca maura) respond to seven species of real and model snakes. Snakes could be local and dangerous to the macaques (i.e., venomous or constricting), local and nondangerous, and novel and dangerous. Macaques reacted most strongly to constrictors (i.e., pythons), exploring them and producing alarm calls, and partially to vipers (both local and novel), exploring them but producing no alarm calls. However, they did not react to other dangerous (i.e., king cobra) or nondangerous species. Our results suggest that moor macaques discriminate local dangerous snakes from nondangerous ones, and may use specific cues (e.g., triangular head shape) to generalize their previous experience with vipers to novel species.

Interactions with humans are jointly influenced by life history stage and social network factors and reduce group cohesion in moor macaques (Macaca maura)

Human-wildlife encounters are becoming increasingly frequent across the globe, often leading people to interact with and feed wild animals and impacting animal behaviour and ecology. Although the nature of human-wildlife interactions has been well documented across a number of species, we still have limited understanding as to why some individual animals interact more frequently with humans than others. Additionally, we lack a comprehensive understanding of how these interactions influence animal social networks. Using behavioural data from a group of moor macaque monkeys (Macaca maura), we used permutation-based linear regression analyses to understand how life history and social network factors jointly explain interindividual variation in tendency to interact with humans along a provincial road in South Sulawesi, Indonesia. As our study group spent only a portion of their time in proximity to humans, we also examined how social network structure changes in response to human presence by comparing social networks in the forest to those along the road. We found that sex, individual network position, and associate network position interact in complex ways to influence individual behaviour. Individual variation in tendency to be along the road caused social networks to become less cohesive when in proximity to humans. This study demonstrates that nuanced intragroup analyses are necessary to fully understand and address conservation issues relating to human-wildlife interactions.

Socially tolerant relationships among wild male moor macaques (Macaca maura)

Researchers are increasingly documenting the existence of social tolerance and affiliative behavior among primate males, including in male-dispersing species. We investigated the nature of male social relationships in a relatively understudied macaque species, the moor macaque (Macaca maura), in order to expand our knowledge of male social relationships in male dispersing primates. The classification of social styles for primates rests largely on data about female social relationships. Therefore, by providing data on male–male relationships, we also contribute to our understanding of social style variation within the genus Macaca. Observations were conducted on a wild yet well-habituated group in Bantimurung-Bulusaraung National Park in South Sulawesi, Indonesia. We collected focal animal and ad libitum data on four adult males, recording social behavior during 209 contact hours over two field seasons in 2010 and 2011. The adult male moor macaques in this study did not interact frequently. Interactions that did occur more frequently involved affiliation rather than aggression, with greetings being the most common form of interaction. Greetings occurred in a predominately neutral context and were more common between specific males with uncertain or ambiguous dominance relationships and low-quality relationships, but the initiation of greetings was not linked to dominance rank. These results suggest that greetings enable males to communicate information about their willingness to invest in the relationship, representing one way for adult males to ease social tension and build social bonds. To expand our understanding of social style variation in Macaca, we compared our data to those published for other macaque taxa. In the present study, the observed pattern of aggression (i.e., low rate, low to moderate intensity and high symmetry) was consistent with the species’ social style classification as highly tolerant. The relatively low grooming rate and low percentage of counteraggression, however, were more consistent with the social style of less tolerant taxa. Further research is needed to determine what factors explain this pattern of social tolerance among male moor macaques.

Yellow-billed malkohas (Phaenicophaeus calyorhynchus) following moor macaques (Macaca maurus) in South Sulawesi, Indonesia

Several authors have reported associations between birds and monkeys in tropical forests (Boinski & Scott 1988, Huettmann 1999, Ruggiero & Eves 1998, Terborgh 1990). By such associations birds are considered to get some benefit, such as protection from predators and/or greater feeding efficiency (Terborgh 1990). In Southeast Asia, however, few reports on such interspecific associations have been available (galetti & McConkey 1998). The exception concerns several species of macaques living on Sulawesi Island, Indonesia (Fooden 1969). Associations between birds and Sulawesi macaques have been descibed by researchers as well as bird-watchers (Coates et al. 1997, Jepson & Ounsted 1997, Martarinza et al. 1994, Whitten et al. 1988). Local people in Sulawesi also know of associations between macaques and certain birds, particularly hair-crested drongo (Dicrurus hottentotus) and yellow-billed malkoha (Phaenicophaeus calyrhynchus). The farmers call these birds ‘burung monyet’ (monkey birds) and use the conspicuous calls of drongos and malkohas as signs of macaques' approaches to their fields (S. Matsumara, pers. obs.).