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

Abstract

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.

Avoidant social style among wild crested macaque males (Macaca nigra) in Tangkoko Nature Reserve, Sulawesi, Indonesia

“…Social style among wild crested macaque males 3 4 37 moor macaque males appear to be similar to extremely tolerant females in their low rates of aggression, low proportions of intense aggression, but more similar to grade 2 and 3 macaques' proportions of counteraggression (Riley et al, 2014). Additionally, a study by Palagi et al (2014) on Tonkean macaques reports sex differences in patterns of consolation (affiliation between victims and third party), highlighting the nuances between male-male and female-female relationships.…”

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

“…Moor macaques live in cohesive multimale, multifemale groups, display female philopatry, and frequently display behavioural synchrony—i.e., engage in the same behaviour in time and space 11,41 . M. maura is a socially tolerant species, characterized by symmetry in aggression, high rates of affiliation and reconciliation, low influence of kinship on social interactions, tolerance of feeding near non-kin, and tension-reducing behaviours during male-male interactions 42,43 . Humans and larger snakes are the only potential predators of this species.…”

“…All individuals were recognizable based on natural markings. Age classes were estimated according to body size and appearance of external genitalia 11,43,45 . Individuals that were not present for the entirety of data collection (n = 1 adult male), as well as infants (n = 2), were excluded from data analysis.…”

“…Location was scored as “along the road” if the individual was on the road or in roadside areas that lacked forest vegetation; all other locations were scored as “in the forest.” We chose a low proximity threshold of 1 m to record nearest neighbours because socially tolerant species often display low interindividual distances 47 . Behavioural states included affiliative behaviour, aggressive behaviour, grooming (allo- and auto-), feeding, foraging, following conspecifics, locomote, male-male greetings, rest, sexual behaviour, and play behavior 43,48 .…”

“…Although dominance rank is a commonly investigated factor in studies of primate social relationships and has been included in previous social network studies and studies on human-macaque interactions 33,58 , we had insufficient data on agonistic interactions to reliably construct individual dominance rank to include as a variable in our analyses. However, moor macaques have more socially tolerant relationships, tolerate proximity to one another while feeding, and likely experience low within-group competition 42,43,59 . These traits, combined with the spatially dispersed nature of provisioning along the road, likely reduces the influence of dominance rank on social interactions and access to provisioned foods.…”