Dodging the moon: The moon effect on activity allocation of prey in the presence of predators

Animals can adapt their activity patterns throughout the circadian cycle. Prey may use moonlight as a predation risk cue and allocate their activity to lower risk periods. Here, we assessed moon transit influence on the activity allocation of nocturnal mammalian prey, in the presence of a predator (pumas, Puma concolor), during different moon phases, through camera trapping in Central Amazon. Thirty camera traps were installed 2 km apart from each other in each of our three study sites. Prey record distributions were assessed across the moon cycle, and their daily activity patterns were described in each moon phase. The record distributions of pacas (Cuniculus paca) (N = 262) and armadillos (Dasypus sp.) (N = 244) were concentrated in darker nights, contrasting with red brocket deer (Mazama americana) (N = 123) and pumas (N = 31), whose records were evenly distributed through the moon cycle. Yet, every prey was found to avoid the brighter times of the night regardless of the moon phase. These findings suggest prey can shift the temporal distribution of their activities under different moon phases when predators are present, perhaps in response to predation risk variations.