Variation in self-directed behaviors prior to acting offers insights into decision-making and social style in wild Tibetan macaques

An ability to recognize individuals and effectively manage social relationships is critical for species living in a complex social environment. Here, we used a focal sampling method to record and analyze rates of self-directed behavior (hereafter SDB, an indicator of anxiety, frustration, and stress that includes self-scratching) in wild Tibetan macaques (<i>Macaca thibetana</i>) prior to approaching another group member. Our goal was to examine the ability of Tibetan macaques to retain and use information on rank and kinship in social decision-making. Specifically, we examined the five minute period prior to approaching a conspecific in order to determine (1) whether individuals who make a decision to approach a conspecific were characterized by an increase in SDB compared to individuals who did not approach a conspecific; (2) the degree to which rank, sex, and kinship had an effect on making a decision to approach, and (3) whether individuals who waited longer to make a decision to approach were characterized by an increase in SDBs. Our results indicate that: (1) individuals who approached a conspecific were characterized by higher rates of SDBs compared to social settings in which a Tibetan macaque did not approach another group member; (2) prior to approaching a higher-ranking group member of the same sex, both the males and females exhibited higher rates of SDBs than when approaching a lower-ranking group member; (3) Females showed no differences in the rate of SDBs prior to approaching a female close kin (sister or mother/daughter) compared to approaching an unrelated or distantly related female; (4) lower-ranking adult males were found to exhibit higher rates of SDBs before approaching a receptive female than did higher ranking males; (5) adult females did not exhibit increased rates of SDBs during the first four minutes prior to approaching a higher-ranking female regardless of kinship, however, their rate of SDBs did increase significantly in the last minute (minute 5) prior to an approach. These results indicate that the social decision-making in both adult male and female Tibetan macaques is associated with a increase in rates of SDBs. Given differences in patterns of social decision-making it appears that Tibetan macaques have sex-specific social styes, with males exhibiting a moderately despotic social hierarchy and females exhibiting a moderately tolerant social hierarchy.