Killer whales are hunting and killing great white sharks in coordinated attacks that strip out the sharks' livers, according to behavioral ecologist Tristan Guttridge, whose findings feature in a new Discovery Shark Week special airing Tuesday at 9pm ET.
"These animals are taking out Jaws... surgically removing their liver and leaving the rest of the animal," Guttridge said.
Guttridge worked with underwater cameraman Kina Scollay and orca expert Dr Renauld de Stephanis, using his own boat as bait, to record for the first time how killer whales train themselves to attack great white sharks through teamwork and surprise. Their recordings showed the orcas communicating using sound frequencies far beyond a white shark's hearing range, then attacking in packs, surrounding the shark, grabbing its fins to control its movement and ripping out its liver to share among the group.
"These guys are the ultimate apex predator on the planet," Scollay said.
A pattern first seen in 1997
One of the first documented cases of a killer whale attacking a great white shark came in October 1997 off the coast of San Francisco. All the white sharks in the area disappeared after that incident.
Guttridge said drone footage has captured white sharks being chased and killed by orcas, but that it does not show the full picture. He said orcas are taking on the ocean's other apex predator, killing whales and feeding on prey ranging from sea leopards to salmon.
In South Africa, dead white sharks have washed ashore with their livers "surgically extracted," researchers said. A shark's liver makes up about 25 percent of its body weight and can weigh hundreds of pounds in a great white. The organ stores large amounts of fuel and oils that help the shark control its buoyancy, making it a rich energy source for a pod of orcas.
Orcas hold a size advantage over great whites, growing more than 30 feet long and weighing over 14,000 pounds, Guttridge said. He said the whales are also teaching themselves new tactics, including traveling thousands of miles to Spain to target small yachts and sailing boats as practice for hunting sharks.
Hundreds of boat attacks in Spain
"In Spain, they're actually attacking and disabling sailboats," Guttridge said. The first report of a ship being rammed by an orca came in May 2020 off the coast of Barbate, Spain. Within weeks, there were 45 reported ship attacks along the same coast, a number that has since grown to more than 600 along the Spanish coast.
Guttridge said several theories have been proposed for the behavior, including retaliation, play and competition, but that one theory in particular stands out: the orcas could be using the boats as a teaching platform for their young. Researchers have documented cases of orcas teaching other orcas to attack, including two orcas in South Africa named Port and Starboard that have been credited with teaching nearby orcas how to hunt and kill great white sharks.
To study the behavior, the researchers deployed a fake rudder on a small boat in Spain's Strait of Gibraltar, similar to the type of boat orcas most commonly attack. The team spotted Atlas, the orca Dr de Stephanis first documented attacking a boat near Spain in 2020, traveling with a pod of seven to eight orcas. Four of them moved in to attack the boat's rudder.
One orca was seen swimming on its side and biting the rudder as the boat tried to escape. The pod eventually crippled the vessel, targeting both the fake rudder and the real one, before turning its attention to a second boat carrying de Stephanis and precisely attacking its rudder in the same way the whales target a shark's pectoral fin.
"There was genuine fear on my part that this boat would go down," Guttridge said. "They were persistent, they didn't back off."
How orcas outsmart sharks
Researchers said orcas use echolocation, sending out high-frequency clicks that bounce off objects in the water to reveal their size and distance. "We're only really beginning to unravel how smart these animals are," Guttridge said. "It's a highly intelligent, social animal."
Orcas form close social groups, often spending their entire lives together and communicating through clicks, calls and pulses, according to the researchers. That gives them an advantage over great white sharks, which communicate at much lower frequencies and rely more on smell to track prey.
"The white shark is a highly visual predator; it has one of the largest proportions of its brain dedicated to olfaction, to smell. It can get up to 30 or 40 mph," Guttridge said. The team suspected orcas were able to sneak up on and kill great whites because they communicate at frequencies outside what sharks typically detect.
To confirm the theory, the researchers returned to sea with a custom sailboat fitted with a stronger rudder, a glass floor for observing attacks and special microphones to record orca communication. Atlas and his pod again approached the modified boat with Guttridge aboard.
One orca broke the boat's rudder entirely, grabbing, twisting and bending it to use as what the researchers call a "control point" on its target. Researchers believe orcas use the same move on great white sharks, controlling the fin to flip the shark upside down and temporarily paralyze it.
"This orca was lining it up at a very specific angle to try and maintain that kind of blind spot position," Guttridge said. "It would be almost impossible for the white shark to detect the incoming orca."
Guttridge said the finding highlighted a key difference between the two predators' hunting styles. He said a white shark attacking a seal relies on stealth and precision at the surface in an all-or-nothing strike, while orcas work in teams, as they did in smashing the rudder and engine of the modified boat.
Before the boat was disabled, the team recorded the vocalizations of an attacking orca for the first time. When analyzed, the calls were all pitched far above a white shark's hearing range, giving researchers evidence that orcas have learned to quietly sneak up on, outnumber and incapacitate sharks to take their livers.
