(i) Analysis of push-up and lateral compression behaviors
Since yellow and blue patches are displayed during push-up and lateral compression events, we focused on these two behavioral traits. We recorded 1) the frequency of push-ups (number of push-ups per push-up event and duration in seconds), 2) the distance between opponents when push-ups and lateral compressions occurred. To do this, we used snapshots of the trials to measure the distance between contestants at each of these specific events with the MB-Ruler 5.0 free software (http://www.markus-bader.de/MB-Ruler/), and 3) scored whether the immediate response of the opponent to a push-up or a lateral compression event was neutral, submissive or aggressive (Table 1).