The societies of many mammals are structured by dominance hierarchies in which individual social rank determines priority of access to resources. Although high social rank is known to affect survival and reproduction among female mammals, its effects upon males are poorly understood because males usually change social groups before breeding, so it is difficult to follow them throughout the lifespan. This research follows male carnivores throughout the lifespan to test hypotheses suggesting that their maternal rank in their natal social group might affect the development of their behavior, their body condition and/or their morphology, and that each of these in turn might affect their survival and reproduction in the natural habitat. This research uses spotted hyenas as model mammals because their societies are rigidly structured by dominance relationships. Specially designed radio collars will be applied to male hyenas dispersing among multiple study groups in Kenya. Methods will include radio tracking of collared males, noninvasive monitoring of their stress hormones, and collection of observational data on their performance in standardized test situations as well as their behavioral interactions with other individuals, using bush vehicles as mobile blinds. These techniques will permit determination of whether or not social rank in the natal group affects male survival and reproductive success long after they leave their natal groups, and if so, how such effects are mediated physiologically. This field project offers unique, rare and highly valuable training opportunities for American graduate and undergraduate students in eastern Africa. In addition, this research will educate and entertain lay audiences via internet coverage, public lectures, museum exhibits and television coverage. Finally this work is expected to enhance efforts focused on the conservation of large mammalian carnivores, both in Africa and around the globe.