Safe and selfish sentinels? An empirically based model — ASN Events

Safe and selfish sentinels? An empirically based model (#177)

Ofri Mann 1 2 , Yitzchak Ben-Mocha 3
  1. Life Sciences, Ben Gurion University - Eilat Campus, Eilat, Israel
  2. Life Sciences, Interuniversity Institute of Marine Sciences, Eilat, Israel
  3. Life Sciences, Tel-Aviv University, Tel-Aviv, Israel

Sentinel behavior in social vertebrates has been considered "selfish" by many theoretical and empirical studies, where sentinels simply chose the "safest" option by assuming an elevated position and increasing their predator detection chances. However, existing models allow for either foraging or sentinel behavior, and fail to include a third option – hiding under safe cover. Based on empirical evidence from Arabian Babbler (Turdoides squamiceps) groups, we argue that such hiding places are frequently used and should also be addressed by theoretical models. By extending previous models to include safe hiding places, we show that coordinated sentinel behavior arises only when considering the reducing effect of predation on group size. When foraging in large groups, or when group size is kept constant, satiated individuals should prefer hiding under safe cover. Our results suggest that sentinel behavior is not the safest option for the individual and that coordinated sentinel behavior may exist, among other reasons, as a result of group augmentation.