Data for: Living in fear: How experience shapes caribou responses to predation risk

Wild prey can reduce predation risk by avoiding areas used by their predators. As they get older, individuals should be able to fine-tune this avoidance based on their increased experience with predators and cues associated with predation risk. Such learning mechanisms are expected to play a key role in how individuals may cope with risk during their life, particularly in altered landscapes where human disturbances have created habitat conditions distinct from those of the past. We studied the role of experience on the avoidance of risky areas by boreal caribou (Rangifer tarandus caribou) in a system where they are under high predation pressure from grey wolves (Canis lupus) and black bears (Ursus americanus). We described the behavioural responses of caribou to variations in the risk of encountering wolves and bears, investigating whether individuals adjusted their level of predator avoidance with passing monitoring years, a proxy of increasing experience. We used telemetry data collected on 31 wolves and 12 bears to map spatial variations in the risk of encountering predators. We used data from 28 collared female caribou monitored for 3–8 years (mean ± SD: 4.4 ± 2.2) to assess trends in the avoidance of risky areas by caribou with passing years. We observed an increase in the avoidance of areas suitable to wolves with passing years, except during winter and calving when females did not adjust their avoidance of wolves. We also found an increase in the avoidance of areas suitable to bears across all study periods. These results suggest that, in most circumstances, caribou became more efficient at avoiding areas selected by their main predators as they gained experience throughout their life. Provided the avoidance tactics observed in this study are heritable and offer fitness advantages to the individuals that display them, our results suggest that caribou populations living in disturbed environments may have the potential to adapt to changing predation risk. Our findings have encouraging implications for caribou and wildlife conservation in general, as they suggest that experience may allow prey to adjust to novel conditions, including higher predation risk.