Fear of the super competitor? Deer respond more strongly to pigs than coyotes

Abstract Wildlife species face complex trade-offs when maximizing foraging efficiency while minimizing risks from predation and competition. Behavioral responses to these pressures often vary based on intrinsic factors like sex, and can have important implications for individual fitness and population dynamics. However, the relative importance of predation versus competition in shaping behavior, and how this differs between sexes, remains poorly understood. We conducted an auditory playback experiment exposing white-tailed deer ( Odocoileus virginianus ) to vocalizations of predators (coyote, Canis latrans ), competitors (invasive wild pigs, Sus scrofa ), and non-threatening controls (birds) at foraging sites. Both adult males and females exhibited the highest probability of flight in response to pig sounds, followed by coyotes. Among individuals that did not flee, only females showed disturbance—moving away from the sound source without abandoning the site—in response to pigs, while only coyotes increased vigilance in both sexes. Pig sounds also significantly reduced feeding time in both sexes, whereas coyotes only reduced feeding time in males. Across behaviors, females often responded more strongly than males, likely reflecting greater susceptibility to competition and predation. Our findings demonstrate that invasive pigs act as “super competitors”, eliciting stronger behavioral responses than native predators.