Are humpback whales saving other species being hunted by killer whales?

Yes. For example, in 2012 in Monterey Bay, California, a BBC team filmed the intervention of two humpbacks to protect a young gray whale being pursued by killer whales. The calf ends up dying, but about fifteen other humpbacks subsequently arrive and position themselves between the killer whales and their prey, preventing them from devouring it. In the course of this confrontation, the humpbacks produce powerful sounds and engage in violent tail-slapping whenever a killer whale approaches and remain “on the lookout” for several hours.

More than 100 such interactions between humpbacks and killer whales were documented between 1951 and 2012 and were used in a study by the National Oceanic and Atmospheric Administration (NOAA) published in the journal Marine Mammal Science in 2016. Researchers estimate that 95% of the killer whales involved were “mammal-eaters” and that in 89% of the incidents observed, humpbacks approached once the killer whales began hunting, and opted to intervene specifically to interrupt the hunt. As for the prey, the vast majority (89%) belonged to other species (cetaceans, pinnipeds and fish). Researchers wonder: why are humpbacks risking their lives and expending energy for other species?