https://phys.org/news/2018-06-threatened-whales-dolphins-predatory-killer.html > Bowers recalls that the pilot whales and dolphins appeared to remain calm when most of the sounds—including many of the killer whale calls—were played into the water. However, he was astonished by the animal's reactions when he broadcast four specific killer whale calls. 'It was crazy to see a group of animals respond so strongly to something you're doing', says Bowers, describing the response of the Risso's dolphins as a stampede and adding, 'The strong and differential responses to this subset of killer whale calls was eye opening'. > Back in the lab, Bowers and Nicola Quick estimated how much energy the animals were using to build a sense of their urgency and reconstructed the dolphin and pilot whales' movements; they noticed that the two species' reactions were completely different. While the pilot whales assembled into a tight group that dived down toward the alarming sound, the Risso's dolphins clustered together and fled in the opposite direction at high speed for more than 10 km.