The male-female health-survival paradox – the phenomenon in modern human societies in which women experience greater longevity but higher rates of disability than men – has far-reaching economic and medical implications. The PLs have spent the past five years carrying out the first examination of the health-survival paradox in a nonhuman animal, a population of wild baboons. Their results indicate that male baboons, along with males of several other primate species, have shorter lifespans than females, a pattern they share in common with humans. On the other hand, aging male baboons experience declines in health that are similar to or more rapid than those in females, making them different from humans in this respect. To move forward with comparative studies that can shed light on the health-survival paradox, the PLs propose to develop a more complete picture of commonalities and differences between humans and nonhuman primates in factors contributing to health and survival. To do so, the PLs will build on findings from the current Program Project grant to pursue four Aims. First, in work that cross-links with Project 2, the PLs will investigate sex differences in social status and social connectedness as risk factors for the steeper health declines seen in male baboons than in females. Because male baboons experience much steeper age-related declines in social status and social connectedness than females, these variables – known to be risk factors for human health and survival – are implicated as key sources of sex differences in this study system. Second, by observing and measuring rates of wound healing and recovery from illness in the baboons, the PLs will generate unique data for comparison with Project 2 on sex differences in recovery and survival after illness. Third, the baboons are a compelling model for understanding hormone profiles that depend on sex and social status, and this will allow the PLs to gain traction on the question of whether stress hormones mediate the relationship between social factors and survival. Fourth, in collaboration with Project 1, the PLs will use unique comparative data that has been gathered from multiple primate species to develop sophisticated modeling techniques that will allow the measurement of sex-specific mortality patterns with greater accuracy and for a wider range of species than ever before measured. Achieving these aims will provide crucial insight into the underpinnings of male-female differences in health and survival and the health-survival paradox.