Killer whales are able to kill and eat blue whales, scientists confirm

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In March 2019, scientists studying whales near southwest Australia came across an oversized sight few had seen before – a pod of killer whales viciously attacking a blue whale.

More than a dozen orcs surrounded the mighty beast. They had already bitten off its dorsal fin and the animal was unable to escape the fast and agile predators. The water was red with the massive creature’s blood, and bits of its flesh were floating around. Scientists have observed an orca forcing its way into the blue whale’s mouth and feasting on its tongue. It took the orcas an hour to kill the blue whale, and once they did, about 50 other orcas showed up to devour the carcass.

Orcas, also known as killer whales although they belong to the same family as dolphins, are apex predators known to prey on almost all species of large whales. But, they generally attack calves and not adults. It was the first time killer whales had been observed successfully killing and eating an adult blue whale.

The attack was the first of three such events that were observed from 2019 to 2021. These events, described in an article published last week in the journal Marine Mammal Science, ended a long-running debate among scientists over whether or not orcas could make a meal from an adult blue whale.

A pod of orcas shooting down a blue whale is “the greatest predation event on Earth, perhaps the greatest since the dinosaurs have been here,” said Robert Pitman, a marine ecologist at Oregon State University and author of the item.

Anecdotal evidence that orcas are able to make a meal from an adult blue whale has been around for a long time, but it wasn’t until 2019 that scientists were able to confirm this with first-hand observation.

“On approach, we were amazed at what we saw,” said Rebecca Wellard, founder and principal investigator of the ORCA project, who was among the researchers who witnessed the 2019 attack. a single event like this, I think it takes a while to process exactly what you see.”

Blue whales, the largest creatures that have ever lived, can grow up to 110 feet in length, but the animal attacked was only 70 feet long, raising the question of whether it was a younger blue whale. But Dr Wellard and his team were able to photograph the blue whale before the killer whales tore it apart. Based on its appearance, as well as the location and time of year it was photographed, they concluded it was an adult pygmy blue whale, a genetically similar subspecies to the most massive of blue whales, but with a smaller size and other distinguishing characteristics.

Pygmy blue whales reach lengths of up to 79 feet, so this animal was most likely an adult.

“I think an adult pygmy blue whale could be mistaken for an ordinary blue whale that wasn’t quite mature,” said Erich Hoyt, researcher at Whale and Dolphin Conservation and author of “Orca: The Whale Called Killer “. He did not participate in the research.

Mr Hoyt said the fact that these killer whales were able to successfully hunt this pygmy blue whale served as strong evidence that they could do the same for even the most massive blue whales. “Blue whales are fast, but orcas are faster,” he said.

The event that Dr Wellard and his team witnessed occurred off Bremer Bay, a biologically rich area where large numbers of orcas, blue whales and other cetaceans can be seen at certain times of the year.

“The killer whales we are looking for off Bremer Bay are rewriting the textbook on what we thought we knew about this species,” Dr Wellard said.

Photographers aboard whale-watching boats in the area have documented two other orca attacks on blue whales since the observed attack in 2019. More than a dozen orcas coordinated to carry out both attacks against juvenile blue whales. While scientists had observed killer whales with dead blue calves in the past, such attacks had yet to be documented from start to finish.

Although orca predation on blue whales is horrendous, scientists say it could be a positive sign for the health of whale species in the region. The whaling industry nearly drove blue whales to extinction, and the fact that there are now enough of them to be preyed upon by orcas may portend population growth.

“What we might see now is a return to ‘normalcy’ as populations of large whales and their predators continue to recover,” Dr Wellard said. “It was perhaps only a matter of time before a sighting like this was made. Nevertheless, these hunts signal a positive step for the populations of both species.

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