Abstract: Many studies have found that experiencing early life adversity (social and environmental stressors such as low socioeconomic status, inadequate nutrition, abuse and neglect, etc.) leads to poor health and/or impaired social function later in life. This is true in a remarkably wide variety of taxa, which raises questions about how early experiences ‘embed’ themselves in the body, as well as whether the adaptive tradeoffs organisms make when dealing with early adversity are primarily driven by short-term or long-term payoffs. Wild savannah baboons, like humans, can face a variety of social and ecological hardships when they are young. These experiences can lead to vastly shortened lifespans, but we do not yet understand the mechanisms by which this occurs. In this talk, I will present new data on the relationships among early adversity, adult social bonds, and hypothalamic-pituitary-adrenal (HPA) axis function in a population of wild baboons in Amboseli, Kenya, which has been studied since the 1970s. I will also discuss ongoing research on competing hypotheses that seek to explain the relationship between early social environments and reproductive outcomes. Longitudinal data from this close human relative provide valuable insights into the biological bases of connections between early experience and adult outcomes in our own species.