In this talk, I will share what I have learned about how endocrine mechanisms interact with environmental and social factors to shape variation in fitness-related outcomes in a wild social mammal. Drawing on nearly three decades of data from free-ranging rock hyraxes (Procavia capensis), I will discuss how male reproductive tactics are associated with divergent investment in sexual signaling, sperm production, and reproductive success, mediated in part by testosterone. I will then present results showing that male longevity is explained by the interaction between testosterone and cortisol. Throughout the talk, I will also discuss evidence for sexual conflict that has emerged from our long-term study and consider the importance of examining sex differences through long-term studies of animals in their natural environments. Together, my findings highlight the role of hormones in mediating mating strategies and life-history trade-offs and demonstrate how phenotypic flexibility can arise from the integration of intrinsic condition and extrinsic pressures in a complex social system.