“Maybe what we’re starting to see now is how the ocean used to be before we took out most of the large whales … As some of these populations continue to recover, we have a better chance to see how normal marine ecosystems function,” he said. Killer whales tend to be opportunists when it comes to feeding on mammals, said one of the authors, Robert Pitman from Oregon State University, so this could be a return to normal as blue whale populations recover after centuries of whaling. They have also been observed attacking deep-diving beaked whales, Antarctic minke whales and yearling humpback whales, using similar pack strategies to hunt. Most killer whale populations specialise in a certain type of prey, but killer whales off Bremer Bay have a particularly diverse diet. This study adds the planet’s largest creature to that list, suggesting the only baleen whale impervious to attack from these apex predators is the adult humpback. Killer whales are known for hunting down large prey, similar to wolf packs, successfully predating on gray whales, sea lions, dolphins and even great white sharks. Females need to feed young and may need to feed more often than males, which possibly makes them more likely to initiate attacks, researchers said. Previously, it had been assumed that for killer whale attacks on large whales to be successful, adult males need to be involved, but all three of these attacks were led by females, which are about 20% smaller. Killer whale pods are matriarchies, led by the oldest female, and any male offspring are descendants of the matriarch. At least 50 turned up to feed on the carcass. The attack was started by 12 orcas, including six females. The killing involved the same strategy of lining up and pushing the whale below the surface, while also attacking its mouth. The third attack was on a yearling, about 12 to 14 metres long, which was chased for 15 miles for 90 minutes. Photograph: John Daw/Australian Wildlife Journeys Large chunks of flesh have been removed from its flanks. Killer whales charge alongside the blue whale calf. There was no evidence of aggression or frenzied feeding, researchers said. Towards the end of the attack, an adult female again put her head inside the blue whale’s mouth to feed on its tongue.įor the next three and a half hours, about 50 killer whales fed off the carcass, bringing large chunks of flesh to the surface, which were torn apart and fed on by various members of the group. It was led by 25 orcas, including 22 females, around 25 miles from the first attack. The next attack a few weeks later was on a blue whale calf between 10 and 12 metres long. The killer whales were not seen on site again. “We visited the kill site for six days after the attack, and for the first few days there was a large slick on the surface where oil was emanating from the carcass on the seafloor,” the researchers wrote. Several dozen birds continued to feed on scraps for days afterwards. In the next six hours, 50 more orcas joined in the feeding, as well as at least 200 flesh-footed shearwaters, more than 20 storm petrels and at least one albatross. The last one swam inside its mouth and started eating its tongue, which is nutritionally dense. After an hour of relentless attacks, three female killer whales lined up side-by-side and rammed the blue whale on its side, pushing it underwater, while two others attacked its head. It was coordinated by at least 12 orcas, led by eight adult females and one male, with younger ones watching.Ġ1:11 Orcas recorded killing and feeding on blue whales in 2019 – videoīy the time observers reached the site, large chunks of skin and blubber had been stripped off the adult blue whale and most of the dorsal fin had been bitten off. The attack in March 2019 was on a healthy adult whale, between 18 and 22 metres long. Many individual females were involved in all three attacks. “Notably, the first whale taken appeared to be a healthy adult.”Īll the attacks happened off Bremer Bay in Western Australia, within 40 miles (60km) of the shore, and were observed from commercial whale-watching vessels. “Here we provide the first documentation of killer whales killing and eating blue whales: two individuals killed, 16 days apart in 2019, and a third in 2021,” researchers wrote in the paper. This research is the first to officially document these killings, including details about how orcas swim inside the mouth of the blue whale to eat its tongue just before it dies. Previously there were reports of these apex predators “chasing” blue whales – which grow up to 33 metres long – but authenticated attacks are extremely rare.
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