Neutral arena setup
Males were allowed to acclimate in captivity for 7 days prior to staging the pairwise contests (Bohórquez-Alonso et al. 2018). The contests were staged in a neutral arena to remove the effect of residency (Sacchi et al. 2009; Abalos et al. 2016), and in a small confined room, free of noises and other distractions. The 42 males were paired by similarity in body mass (mean mass difference = 0.64 g) and never exceeding an SVL difference of 2 mm between them (mean SVL difference = 0.72 mm) (Bastiaans et al. 2013). This removes the size effect, which is not an objective of the present study, but is an important predictor of dominance in lizards (e.g. Sacchi et al. 2009). Contestant males were transferred into an artificial arena that was 60 cm width x 80 cm length x 48 cm height which was set up with sandy substrate covering the bottom. The arena was made up of acrylic sheets and covered on three sides while the fourth side was left uncovered for behavioral recording using a digital video camera. A 75W thermal lamp was set up directly above a central rock. The arena was divided into two parts at the beginning of each trial using a removable partition of opaque plastic. The trials took place on 5 consecutive days between the 30th of May and 3rd of June 2014 from 8:00 am to 6:00 pm. Each lizard was placed at opposite ends of the partition and allowed 5 minutes to acclimate to their space. After this acclimation period the partition between the two sides of arena was removed and the behavior of the lizards was filmed for 20 minutes without any human presence in the room. Before each subsequent trial, sand substrate was changed to avoid the effects of any olfactory cues from previous trial (Bastiaans et al. 2013). We visualized the videos and noted every behavior shown by contesting lizards.