Grouping in prey like antelopes reduces:
Living in a group can lower each antelope's probability of being killed through several mechanisms. More individuals can detect predators earlier, coordinated escape can confuse an attacker, and the dilution effect spreads a given attack risk across many potential targets. Individuals near the center may also reduce their exposure through selfish-herd positioning. A larger aggregation may be easier for predators to notice, so grouping does not necessarily reduce predator attraction, yet per capita mortality can still decline once an attack occurs. The benefit concerns individual risk rather th
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 10