Relationship between the frequency of ritual (a) and affiliative (b) interactions per hour (model residuals controlled for the effect of the time after integration) and the dominance rank of stallions in 2009 (black square) and 2010 (empty squares; mean±SE per rank).

<p>The best fit (quadratic) is indicated with a solid line for 2009 and dashed line for 2010 data. Residuals represented stallions that had more interactions than predicted by the time after integration. Higher dominance ranks indicate higher-ranking individuals.