Killer whales (Orcinus orca) feeding on schooling herring (Clupea harengus) using underwater tail-slaps: Kinematic analyses of field observations

When killer whales slapped the herring successfully, disoriented herring appeared on the video at approximately the time of maximum fluke velocity, in synchrony with a loud noise, This noise was not heard when the tail-slaps 'missed' the target, suggesting that the herring were stunned by physical contact, Killer whales then ate the stunned herring one by one. Of the tail-slaps observed, 61% were preceded by lunges into the school. We suggest that lunging was aimed at directing the school rather than at capturing the herring, since it occurred at a relatively low speed and there were no observations of the killer whales attempting to capture the herring during lunging behaviour, Given the high performance of the tail-slaps in terms of speed and acceleration, we suggest that tail-slapping by killer whales is a more efficient strategy of prey capture than whole-body attacks, since acceleration and manoeuvrability are likely to be poor in such large vertebrates.