Abstract Prey must balance the energetic benefits of foraging with avoiding predation risk. The risk-reward trade-off, a cornerstone of behavioural ecology, hinges not only on realized predation risk but also on how prey perceive that risk. However, the risk prey animals ascribe to the habitats they use is frequently evaluated by quantifying antipredator behaviours, which may be conflated with behaviours resulting from different environmental pressures. We used non-behavioural data to test assumptions about which habitats prey perceive as risky by pairing observations of elk (Cervus canadensis) habitat use with neurochemical responses measured from faecal hormones: glucocorticoids (GC), which reflect stress from perceived risk and hunger, and triiodothyronine (T3), which increases with energy intake. Elk had lower GC and T3 in the forest compared to cropland, a potentially risky but energetically rewarding habitat. In cropland, elk produced more T3, indicating greater foraging rewards. Surprisingly, GC levels were consistent in cropland, even during the daytime when human activity—and putative risk—peaked. The lack of risk responsiveness highlights that perceived risk is context-dependent, likely integrating energetic rewards and periodic encounters with predators rather than reflecting a blanket assessment of habitat. We reveal that prey animals likely mitigate risk at fine temporal scales, and are therefore capable of sophisticated assessments of the habitats they use beyond simple habitat-risk associations. Importantly, our results suggest that putative landscapes of fear may not reflect expected costs of risk for prey.
Newediuk et al. (Wed,) studied this question.