Ground squirrels Holekamp studied the proximal factors influencing dispersal from the natal site by Belding's ground squirrels in the
Sierra Nevada of California. Holekamp's data supported an "ontogenetic switch" hypothesis, suggesting that natal dispersal behavior by male squirrels is triggered by attainment of a particular body mass or body composition, or some combination of these variables. Holekamp also tested hypotheses about the endocrine mediation of natal dispersal, finding that the behavior was mediated by organizational effects of androgenic hormones. Later, Holekamp's first PhD student, Scott Nunes, found that perinatal exposure to testosterone determines the probability of dispersal, whereas the amount of energy a ground squirrel has stored as fat strongly influences the timing of its dispersal. Together with P. W. Sherman, Holekamp summarized her work on natal dispersal in a 1989 paper published in American Scientist that addressed the question of why male ground squirrels disperse at all four levels of analysis suggested by
Niko Tinbergen.
Spotted hyenas From 1988 until 2025, Holekamp served as Director of the Mara Hyena Project, a long-term field study of free-living spotted hyenas in southwestern
Kenya. Her early hyena work, conducted in collaboration with Laura Smale, addressed the question of how females come to dominate males during the course of their early social development. Holekamp and Smale found that young hyenas of both sexes assume social ranks immediately below those of their mothers, and that females only come to dominate males when males disperse from their natal social group. Holekamp and her students went on to study social rank and reproductive success, hunting success, behavioral and hormonal changes associated with natal dispersal behavior, and mating strategies in spotted hyenas. Together with S.M. Dloniak and J. A. French, Holekamp found that both male and female cubs born to mothers with high concentrations of androgens during late pregnancy exhibit higher rates of aggression than cubs born to mothers with lower androgen concentrations. Because spotted hyenas live in social groups of the same size and structure as troops of many old-world primates, Holekamp and her students used spotted hyenas as a model system for testing hypotheses about the evolution of large brains and enhanced intelligence. Holekamp and her students have also made contributions elucidating the immune function of spotted hyenas, their microbiome, their conservation and management, their cooperative defense of resources, and their social dynamics. == References ==