As It Happens6:30Footage shows pod of orcas killing a great white shark and devouring its liver
Great white sharks can now not declare the title of high predator — at the very least not off the coast of South Africa.
New drone and helicopter footage shows a pod of orcas ruthlessly pursuing a great white shark in Mossel Bay earlier than stepping into for the kill. The grisly video culminates with one of the killer whales gobbling up a giant chunk of the shark’s liver.
Scientists have lengthy suspected that killer whales have been searching sharks off South Africa’s coast and driving them from their pure habitat. Now they’ve “irrefutable proof,” says shark biologist Alison Towner.
“When I noticed the footage, of course, it simply confirmed all the things,” Towner, a PhD candidate at South Africa’s Rhodes University, advised As It Happens host Nil Köksal.
“And as haunting it’s to see the behaviour, one can not help however be awed by it as nicely. It’s actually fairly a novel piece of pure historical past to look at.”
Towner is the co-author of a new paper analyzing the footage, which was printed this week within the journal Ecology.
WATCH | Killer whales take out a great white shark:
Towner says there’s been mounting proof of orcas searching great whites off South Africa since 2017.
“We had carcasses that have been washed up, ripped open, livers lacking. We had sightings of orcas within the space, [followed by] disappearances of the white shark,” she stated.
Not solely does the brand new footage give her the smoking-gun proof she’s been in search of, however it permits scientists to look at precisely how the hunt performed out.
The video — a compilation of helicopter and drone footage of the identical hunt on May 16 — shows 5 orcas working collectively to kill a shark.
As one orca hones in on its prey, as a substitute of fleeing, the shark swims tight circles, mimicking an invasive method that turtles and seals use when attempting to flee great whites.
It’s a transfer that typically works out for a shark’s prey — however it did not assist this great white escape its hunters. That’s as a result of orcas, not like great whites, hunt in packs.
“I at all times seek advice from the orcas as being just like the wolves of the ocean,” Towner stated. “They’ve form of bought the sting on this as a result of, you already know, they’re co-ordinated and they have teamwork, whereas the white sharks are on their very own. They’re caught abruptly and they’re mainly simply panicking.”
It’s no straightforward feat to make a great white shark panic. But there’s a cause that orcas are known as killer whales — though they’re, the truth is, dolphins.
“What does all people affiliate an orca with, usually? We all assume of Free Willy, proper? Or Sea World? And we expect cute and cuddly, and clearly very charismatic,” Towner stated.
But orcas, like great whites, are thought of apex predators of the ocean.
“They are prolific hunters. They’re extraordinarily environment friendly. They’re reasonably savage really, as a result of they’re so good at what they do,” she stated.
“White sharks have this very apex predator function, and they’re fairly feared. But now they’ve positively been knocked off the highest pedestal right here.”
Josh D. McInnes, a marine mammal researcher on the University of British Columbia who has studied orcas searching giant mammals, says there are a quantity of attainable causes the orcas are focusing on sharks.
“Killer whales could kill white sharks primarily based on competitors for assets, perceived threat to younger calves in a pod, or for meals,” he advised CBC Radio in an electronic mail.
“The liver of sharks is wealthy in vitamins and oil, and makes up a giant proportion of the shark’s anatomy. It would make sense for killer whales to feed on this organ.”
Jenny L. Atkinson, govt director the Whale Museum in Washington, says that whereas this footage is novel, the behaviour seemingly is not.
There have been studies of orcas killing great whites in California for the reason that late ’90s. And a 2109 examine discovered that when orcas present up in shark-infested waters, great whites flee.
“With extra folks watching and video extra accessible, we’re going to be documenting extra behaviours that appear new or distinctive to us — however it’s seemingly not new to them,” Atkinson stated in an electronic mail.
Driving the sharks away
Towner says the hunt caught on movie is an element of a broader sample. In reality, she and her colleagues suspect that three different sharks have been killed by that very same orca pod that day.
And they consider it began with two orcas generally known as Port and Starboard — the latter of whom appeared within the footage chomping down on the shark’s liver.
The lethal duo, Towner stated, seem to have be passing their shark-hunting strategies to different orcas. And the sharks are responding, she stated, by getting the heck out of dodge.
After the video was filmed, no great whites have been seen within the space for 45 days. They began to reappear in the summertime, however then one other mangled great white shark carcass washed ashore.
“Since then, there have not been any white sharks again in Mossel Bay,” she stated.
Towner says she’s apprehensive what it will in the end imply for the long run of South Africa’s great white shark inhabitants, and what their loss will imply for the ecosystem at giant.
The coast of South Africa, she says, is the sharks’ pure feeding floor. And it is unclear the place the fleeing sharks have taken refuge.
“How many extra occasions can it occur earlier than your entire inhabitants is displaced?” she stated. “It’s actually exhausting to foretell what is going to occur.”