Work

Diurnal–nocturnal shifts in coalition strategies among male Tibetan macaques ( Macaca thibetana )

Year: 2026

Type: article

Abstract: Coalitionary behavior is a key strategy for social animals to cope with competition. Although male coalitions during the daytime have been extensively studied, nocturnal coalition patterns and diel variations remain poorly understood. We used a starlight imaging system to record males' nocturnal behavior in a group of free-ranging Tibetan macaques, simultaneously collecting diurnal data. Agonistic support was used as an indicator of coalition success. Results showed that young adult males exhibited significantly higher frequencies of nocturnal coalition support and recruitment than during the daytime, while middle-aged and old males showed no significant diurnal–nocturnal differences. Affiliative behaviors promoted coalition formation during both day and night. However, daytime coalitions were influenced by David's score (DS) differences, occurring more frequently between males with smaller rank differences. Coalition success rate increased with the recruiter's DS value during daytime, but at night, the recruiter's social centrality became the determining factor. We conclude that Tibetan macaque males exhibit significant diurnal–nocturnal differentiation in coalition strategies. Diurnal coalitions are jointly influenced by social rank and affiliation, while nocturnal coalitions depend more on social centrality and affiliative relationships. This study provides new insights into the behavioral plasticity and environmental adaptability of social animals.

Source: Current Zoology

DOI: 10.1093/cz/zoag017