Whereas human activities are leading to declines in many wildlife populations, some species appear to be faring relatively well in the face of environmental change by demonstrating a great deal of phenotypic plasticity. I investigated the mechanisms underlying such flexibility in spotted hyenas (Crocuta crocuta), a species that persists in areas rapidly changing due to human activity. Specifically, I tested an hypothesis that the developmental trajectory of spotted hyenas is shaped by anthropogenic disturbance, and that hyena mothers transmit information about anthropogenic disturbance in their environment to their offspring via behavioral and/or physiological maternal effects. To test this hypothesis, I used longitudinal analyses of hyena behavior and physiology as well as cross-sectional analyses comparing hyenas in “high- disturbance” and “low-disturbance” areas of the Masai Mara National Reserve in Kenya.First, I conducted field experiments to assess differences in personality among juvenile spotted hyenas living in high- and low-disturbance areas. I found that juveniles in the high- disturbance area were significantly less neophobic and more exploratory, but also less bold, than those in the low-disturbance area. Because most of the subjects tested were residing at the communal den, where cubs are not directly exposed to anthropogenic activity, these findings suggested that maternal effects may be shaping these differences. Next, I determined socio- ecological correlates of juvenile fecal glucocorticoid (fGC) concentrations and tested the hypothesis that disturbance-related differences in fGC concentrations mediate differences in juvenile personality. I did not find strong support for this hypothesis because, although juvenile females showed higher fGC concentrations in high-disturbance than low-disturbance areas, there were no significant disturbance-related differences in fGC concentrations among juvenile males, lactating females, or pregnant females. Finally, I explored variation in maternal behavior among spotted hyenas. I found that mothers showed significant individual variation in the amount of time they spent grooming cubs, but little variation in the amount of time they spent nursing and in close proximity to cubs, or in how they maintained proximity with cubs. I also found support for the hypothesis that disturbance-related differences in maternal behavior mediated the differences I documented in juvenile personality. Using spatial data from mothers fitted with GPS collars, I found that mothers in the high-disturbance area showed significantly lower rates of den attendance than did mothers in low-disturbance areas. While at the den, mothers in high-disturbance spent more time nursing their cubs, but also less time close to their cubs and higher rates of leaving their cubs, than did mothers in low-disturbance.Overall, our results provide insights into how plasticity may be affording spotted hyenas the ability to persist in disturbed areas. None of the maternal behaviors measured were significantly associated with offspring survival, although maternal effects on offspring boldness may positively affect cub survivorship in high-disturbance. Therefore, juvenile resilience to variation in maternal behavior and an early period buffered from disturbance at the communal den may allow mothers to alter their behavior in response to disturbance without negatively affecting offspring survivorship.
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