There's one beast in all the ocean that strikes terror even into the heart of the great white shark, once regarded as the most fearsome predator in the sea.
Off the coast of South Africa, a pair of orcas (Orcinus orca) is known for terrorizing white sharks (Carcharodon carcharias) so relentlessly that the sharks have fled from their own feeding grounds.
Now, for the first time, a completely unrelated pod of orcas has been caught harrying white sharks off the coast of Mexico – and their hunting strategy is nothing short of ingenious.
Orcas highly prize the sharks for their rich, nutritious livers. The orcas of Moctezuma's pod – previously spotted killing whale sharks – have found a way to completely immobilize the sharks before they go in to slurp those livers out like the delicacy they are.
Related: Great White Sharks Were Scared From Their Habitat by Just Two Predators
"I believe that orcas that eat elasmobranchs – sharks and rays – could eat a great white shark, if they wanted to, anywhere they went looking for one," says marine biologist Erick Higuera Rivas of Conexiones Terramar and Pelagic Life.
"This behavior is a testament to orcas' advanced intelligence, strategic thinking, and sophisticated social learning, as the hunting techniques are passed down through generations within their pods."
White sharks are among a number of animals that display a bizarre behavior when flipped upside down: They go completely limp and docile, a behavior known as tonic immobility. In some species, such as opossums, this is known as playing dead, a strategy for escaping the notice of a predator, but it's not known why sharks do it.
Higuera and his colleagues have been studying one pod for some time now, a fascinating group of orcas led by a male named Moctezuma that seems to be developing a prey specialization for elasmobranchs. That's the group of cartilaginous fish that includes sharks and rays.
Here's another thing about orcas. They're technically all one species, but there are differences between groups, known as ecotypes. These can include subtle physical differences, but they also include feeding strategies. Some specialize in eating fish like salmon; others might prefer a diet of seals, or even target whales as their prey of choice.
The orcas of the Gulf of California, which include Moctezuma's pod, haven't been assigned a specific ecotype but are considered opportunistic generalists that hunt and eat whatever's available. So, seeing a subgroup starting to split away and specialize? That's pretty dang interesting.
In the course of their investigation into the orcas of the Gulf of California, the scientists not only observed a group of orcas feasting on white sharks twice, but they also managed to capture the hunts on film in vivid detail, both with aerial drone cameras and underwater cameras.
The results show a considered and coordinated strategy that takes advantage of the sharks' weakness – that tonic immobility. On both occasions, a group of five adult orcas was observed closing in on a juvenile white shark, working together to flip it upside down.
"This temporary state renders the shark defenseless, allowing the orcas to extract its nutrient-rich liver and likely consume other organs as well, before abandoning the rest of the carcass," Higuera says.
The first occasion took place in August 2020, a hunt in which two sharks were killed. The second took place in August 2022. This timing suggests there may be a seasonal element to the hunts, possibly related to the shark pupping season. On both occasions, the orcas emerged from the hunt with their prize, leaving the rest of the shark uneaten.
This is because the livers of white sharks are huge and full of sustenance; the organ acts as a store for the fats and oils that sustain the sharks on their epic migratory journeys, a rich reward for a hungry orca. For both hunts, the orcas also shared the liver among the pod, including the calves.
As for the hunting of juveniles, the researchers believe the practice may be part of a strategy to minimize the risk of injury to the hunting orcas.
"Adult white sharks react quickly to hunting orcas, completely evacuating their seasonal gathering areas and not returning for months," says marine ecologist Salvador Jorgensen of California State University.
"But these juvenile white sharks may be naive to orcas. We just don't know yet whether white shark anti-predator flight responses are instinctual or need to be learned."
Since the 1990s, there have been several observations of orcas hunting elasmobranchs, including whale sharks.
So far, however, Moctezuma's is the only pod known to have such a strong focus on elasmobranch prey. Further research, the team suggests, should focus on determining whether orcas are regularly hunting white sharks in the Gulf of California, and how frequently such attacks occur.
"Generating information about the extraordinary feeding behavior of killer whales in this region will lead us to understand where their main critical habitats are, so we can create protected areas and apply management plans to mitigate human impact," says marine biologist Francesca Pancaldi of the Interdisciplinary Center for Marine Sciences in Mexico.
The research has been published in Frontiers in Marine Science.