Shimmering is a collective defense behavior that researchers have observed in giant honeybee colonies. When shimmering, different groups of bees flip their bodies up and down in what looks like waves. This defense is initiated when hornets hover near a colony, serving to deter the hornets from approaching the bees. Researchers hypothesize that this behavior is a specialized defense response to hornets, as it is not observed when other, larger predators approach the colony.