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In March 2019, scientists studying whales near Southwest Australia stumbled upon a super-sized sight few had ever seen before – an orca pod violently attacking the blue whale.
More than a dozen orcas surrounded the mighty beast. They had already severed its dorsal fin, and the animal could not escape from fast and agile predators. The water ran red with the giant creature’s blood, and bits of its flesh spilled out. Scientists have observed an orca burrow into the mouth of a blue whale and feast on its tongue. It took an hour for the orcas to kill the blue whale, and once they did, it emerged to devour about 50 orca carcasses.
Although they belong to the same family as dolphins, orcas, also known as killer whales, are apex predators known to feed on nearly every large whale species. However, they usually go after calves, not adults. This is the first time orcas have been seen successfully killing and eating an adult blue whale.
The attack was the first of three such incidents witnessed from 2019 to 2021. These events described in an article published Last week in the journal Marine Mammal Science, he ended a long-running debate among scientists about whether orcas can eat from an adult blue whale.
“It’s the largest predatory event on Earth, perhaps the largest since dinosaurs were here,” said Robert Pitman, a marine ecologist at Oregon State University and author of the paper, an orca pod that preyed on a blue whale.
Anecdotal evidence has long existed that orcas can eat from an adult blue whale, but it wasn’t until 2019 that scientists were able to confirm this through firsthand observation.
“As we approached, we were stunned by what we saw,” said Rebecca Wellard, founder and principal investigator of Project ORCA, who was among the researchers who witnessed the 2019 attack. “When faced with such a unique event, I guess it takes some time to process what you see.”
Blue whales, the largest living creature, can grow up to 110 feet long, but the attacked animal was only 70 feet long, raising questions about whether it was a younger blue whale. However, Dr. Wellard and his team were able to photograph the blue whale before the orcas tore it apart. Based on its appearance and the location and time of year it was photographed, they concluded that it was an adult pygmy blue whale; This is a subspecies that is genetically similar to the most massive of the blue whales, but smaller in size and a smaller subspecies. other distinguishing features.
Pygmy blue whales reach a length of 79 feet, so this animal was most likely an adult.
“I think a fully grown dwarf blue whale can be mistaken for a normal immature blue whale,” said Erich Hoyt, a research fellow at Whale and Dolphin Conservation and author of Orca: The Whale Called Killer. He was not involved in the research.
Mr Hoyt said that the fact that these orcas were able to successfully hunt this dwarf blue whale is strong evidence that they can do the same to even the largest blue whales. “Blue whales are fast, but orcs are faster,” he said.
Dr. The event that Wellard and his team witnessed took place off the coast of Bremer Bay, a biologically rich area where large numbers of orcas, blue whales and other marine mammals can be seen at certain times of the year.
Dr. “The killer whales we studied off Bremer Bay are rewriting the textbook we thought we knew about this species,” Wellard said.
Photographers on whale watching boats in the area have documented two more orca attacks on blue whales since the attack observed in 2019. More than a dozen orcas were coordinated to carry out both attacks on baby blue whales. While scientists have observed orcas with dead blue whale calves in the past, such attacks have yet to be thoroughly documented.
While the predation of blue whales by orcas is dire, scientists say it could be a positive sign for the health of whale species in the area. The whaling industry has nearly driven blue whales to extinction, and the fact that there are now enough of them to be hunted by orcas could indicate population growth.
Dr. “What we can see right now is a return to ‘normalcy’ as large populations of whales and their predators continue to recover,” Wellard said. “It may be a matter of time before such an observation is made. However, these hunts mark a positive step for populations of both species.”
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