A Average-linkage cluster diagram, based on association indices (Simple Ratio Index) among the three second-order alliances used in this study (KS = blue, PD = red, RR = yellow) over three time periods (2001–2006, 2009–2014, 2015–2019), demonstrating the stability of these second-order alliances. B Boxplots of association indices (also referred to as dyadic relationship strengths) during the playback study period (2018–2019), with actual values (coloured circles) for each second-order alliance (KS, PD, RR), as well as association indices between pairs of males in different second-order alliances (i.e. third-order allies). The solid grey horizontal lines represent medians, the boxes represent quartiles and the vertical lines represent the 1.5× interquartile ranges. The dashed horizontal lines delineate comparable bond strengths between male dyads within the same second-order alliance and male dyads at the third-order level. C Network plot of the three second-order alliances (N = 14 males) during the playback study period (2018–2019), with males colour-coded by alliance membership and purple edges representing comparable bond strengths between second- and third-order alliance levels (see B).