Human shields alter antipredator behavior in Guenther's dik-dik (Madoqua guentheri)

Human activities affect landscape use by wildlife, with many predators actively avoiding areas near humans. In human-occupied areas, prolonged habituation to human activity could therefore lead to relaxed antipredator behavior by prey species, which can be detrimental when predators return or if individuals are translocated to new areas that host predators. We conducted behavioral trials to test whether exposure of Guenthers dik-dik (Madoqua guentheri) to human activity affected habituation to humans and, by extension, response to predation cues. We hypothesized that dik-diks living in areas with higher levels of human activity would exhibit shorter flight initiation distances and spend less time responding to predation cues than those in areas with less human activity, but would respond more strongly to non-specific predation cues (i.e., alarm calls from white-browed sparrow-weavers, a locally common bird) than to cues associated with predators that avoid human activity (i.e., hyena vocalizations). Flight initiation distance and responses to both sparrow-weaver alarm calls and hyena vocalizations varied predictably with differences in human activity: dik-diks living in areas with more human activity had shorter flight initiation distances and spent less time responding to predation cues than those living in areas with less human activity, but responded more strongly to the sparrow-weaver alarm calls than hyena vocalizations in the area with the highest level of human activity. As human populations expand and overlap increasingly with predators, human settlements and activities may increase susceptibility of prey to predators by increasing prey naivety to predators that avoid humans. These results are particularly relevant for ecotourism in working landscapes and translocation of habituated animals, both of which may increase prey naivety.