Mate-poaching involves attempting to mate with someone who is already in an existing relationship. Mate-poaching is risky, with the possibility of retaliation from the cuckold or opprobrium from the social group. This begs the question: Why mate-poach, when there are so many eligible mates available? We are interested in understanding whether mate-poaching confers mating benefits (Arnocky, Sunderani, & Vaillancourt, 2013), and which physiological, behavioral, and personality traits predict successful mate-poaching (Sunderani, Arnocky, & Vaillancourt, 2013).