Abstract 14 – When Apex Predators Become Prey: Testing the Risk Allocation and Starvation-Predation Hypothesis in the American Black Bear

Emily Davis, Daniel Bjornlie, Ryan Kindermann, Daniel Thompson, Joseph Holbrook

Tradeoffs between risk and reward aid in understanding and predicting behavioral responses
within predator-prey systems. Prey species must balance the risk of predation while acquiring
key resources for survival and reproduction. This balancing act has established key ecological
concepts such as the risk allocation hypothesis and the starvation-predation hypothesis, which
suggests prey temporally avoid risk when spatial avoidance is unattainable and individual
nutritional state modulates anti-predator behavior, respectively. While these foundational
concepts are classically studied in predator-prey systems, and more recently between meso-
predators and apex predators, dynamic sources of risk in human-dominated landscapes have
indicated the importance of extending the classic predator prey-model to a human-prey model.
Mortality risk generated by hunter harvest of American black bears (Ursus americanus)
provides an unconventional system to test and extend foundational hypotheses in predator-
prey ecology. We assessed if black bears balanced mortality risk with the spatially coincident
reward of food-laden bait. According to the risk allocation hypothesis, we assessed if black
bears selected for bait differently according to time of day, sex, and age. We additionally
determined if season, alternative forage around bait, and body fat affected selection of bait to
test the starvation-predation hypothesis. Black bears temporally avoided risk associated with
daytime hunting hours and altered risk taking behavior based on age, sex, and body condition.
We provided support for both hypotheses, and suggest that risk is disproportionally distributed
among individuals. Extending foundational predator-prey understandings to a human-predator
system provided empirical evidence of how large carnivores contend with risk, and supports
management implications of hunter preference when hunting bears over bait.