In March 2019, researchers off the coast of southwestern Australia witnessed a gruesome scene: a dozen orcas ganging up on one of the biggest creatures on Earth to kill it. The orcas devoured huge chunks of flesh from the flanks of an adult blue whale, which died an hour later. This was the first-ever documented case of orca-on-blue-whale predation, but it wouldn't be the last.
Frequent interactions with humans through boat traffic and fishing activities may also drive orcas to learn new behaviors. And the more their environment shifts, the faster orcas must respond and rely on social learning to persist. Taking down a blue whale"requires cooperation and coordination," Pitman said. Orcas may have learned and refined the skills needed to tackle such enormous prey in response to the recovery of whale populations from whaling. This know-how was then passed on, until the orcas became highly skilled at hunting even the largest animal on Earth, Pitman said.
Tongue is not the only delicacy orcas seek out. Off the coast of South Africa, two males — nicknamed Port and Starboard — have, for several years, been killing sharks to extract their livers. "Because there are more cameras and more boats, we're starting to see these behaviors that we hadn't seen before," Weiss said.
"This behavior may be being shared between individuals, and that's maybe why we're seeing an increase in some of these mortality events," McInnes said. Giles and her colleagues study an endangered population of salmon-eating orcas off the North Pacific coast. Called the Southern Resident population, these killer whales don't eat mammals.