Incredible photos show the killing of a blue whale by a pod of orcas, documenting for the first time the largest animal on the planet being hunted

• New photos document the breakthrough study showing orcas killing blue whales in Australia.
• This study has proven such an event is possible, something that has been hotly debated for years.

For the first time, a pod of orcas — also known as killer whales — has been observed hunting and killing adult blue whales, the largest animal on the planet.

Marine scientists from Cetrec WA (Cetacean Research) recently published a study documenting the grisly, but important breakthrough, findings. They detailed how the killer whales swam inside the mouth of the enormous whales to eat their huge, nutritionally rich tongues just before they died.

While there has been anecdotal evidence of the orcas chasing and attacking blue whales that can grow to more than 100 feet long and weigh up to 200 tonnes, killing has never been scientifically documented, John Totterdell, the senior author on the paper, told Insider.

"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," the researchers wrote in the paper. "Notably, the first whale taken appeared to be a healthy adult."

The researchers arrived at the first killing of a 72-foot-long blue whale to see large chunks of skin and blubber having been gouged from its body and with most of the dorsal fin having been bitten off.

It was followed by relentless attacks by the orcas, where three lined up against the blue whale and pushed it underwater, while two attacked its head.

The study explains that 50 orcas joined the pack for six hours to feed on the carcass.

"This study, combined with our recent research, highlights the need for increased understanding of killer whale population ecology so we can better determine their impact on the marine ecosystem in Australian waters," says Totterdell.

Settle a debate

Totterdell also told Insider that there has been a long-had debate amongst marine biologists about if orcas are able to kill a giant blue whale, saying that it had been the "dominant school of thought" that it's not possible.

However, this new study poses breakthrough evidence that orcas prey on the world's biggest creature, and may even have been happening for centuries, Totterdell said.

Previous studies had concluded that whale attacks had to be executed by the biggest orcas — who are male and can grow to 30 feet in length — to be successful. But the new research documented that the blue whale killings were led by female orcas, with the study saying that the drive to feed their offspring could make them more aggressive.

New whale world

One of the things this study represents, Totterdell told Insider, is the exciting things we have to learn about what it is like to have an ocean fully and sustainably populated with whales.

"No one alive today has seen an ocean full of whales," he said.

"None of us have known an ocean where they weren't depleted. Now we have to learn what it's like to have this population, and that's exciting. For the next decades to come, we're going to work out what the new capacities of our ecosystems are."

The International Whaling Commission estimates that blue whale populations are increasing by 2.4-8.4% per year, with commercial whaling having been banned in 1986 after they were hunted to near extinction. The global blue whale population is estimated to be 5,000–15,000 mature individuals as of 2018.

"I doubt whether they're having a big effect yet on blue whales," he said Totterdell. "But look, we've seen one, we'll have to watch what happens over the next few years. It's all new. That's what's exciting."