Combining scientific observations with Canadian Inuit traditional knowledge has provided new insights on how killer whales (Orcinus orca) in the Arctic eat and behave. Biologists from Manitoba visited 11 Canadian Nunavut Inuit communities and collated information from over 100 interviews with hunters and elders as part of this research. They published their results yesterday in the open access journal Aquatic Biosystems, saying that the increase in hunting territories available to killer whales in the Arctic due to climate change and melting sea ice could “seriously affect the marine ecosystem balance.” Killer whales are top marine predators wherever they are found. The whales “seem to eat everything from schools of small fish to large baleen whales, over twice their own size,” reported the biologists. “Aarlirijuk,” or the fear of killer whales, apparently influences the behavior of killer whales’ prey. Smaller mammals seek refuge in shallow waters or on shore, and larger prey run away, dive deep, or attempt to hide among the ice. Even narwhal, which are capable of stabbing a killer whale with their tusks (although this is likely to result in the deaths of both animals), will run to shallow waters and wait until the whales give up. The type of reported prey varied between areas. Most incidences of killer whales eating bowhead whales occurred in the Arctic’s Foxe Basin, while narwhal predation was more frequent around Baffin Island.Inuit were also able to describe first-hand how killer whales hunted, including several reports of how killer whales co-operated to kill the much larger bowhead. During the hunt some whales were seen holding the bowhead’s flippers or tail, others covering its blowhole, and others biting or ramming to cause internal damage. Occasionally dead bowheads, with bite marks and internal injuries but with very little eaten, are found by locals. In this research, the Inuit who were consulted about the diets of killer whales reported that killer whales would ‘eat whatever they can catch’, mainly other marine mammals including seals (ringed, harp, bearded, and hooded) and whales (narwhal, beluga and bowhead).