Some Orcas Are Flipping Juvenile White Sharks and Devouring Their Livers

Great white sharks are used to being at the top of their oceanic food chain. But even these feared predators sometimes find themselves as prey rather than predators. Groups of orcas, or killer whales, have been known to prey on weaker or younger sharks. But evidence of great white shark attacks and exactly how these two fearsome sea denizens interact is slim.

Now, a new study published in Frontiers of marine science has revealed how a pod of shark-hunting orcas that roam the Gulf of California are stalking and killing great white sharks.

Learn more: Orcas can devour marine mammals, but they generally avoid harming humans

Why do orcas hunt sharks?

Researchers found that in two separate incidents, a bull named Moctezuma led a pod of orcas to focus on young sharks too inexperienced to know how to flee. The orcas stunned the sharks by knocking them over, leaving them helpless.

Then they overwhelmed the sharks and ate their foie gras. According to 2024’s Frontiers in Marine Science, this group has previously been observed hunting whale sharks – the world’s largest fish – but this is the first evidence that these orcas are targeting great white sharks.

“This behavior speaks to the advanced intelligence, strategic thinking and sophisticated social learning of orcas, as hunting techniques are passed down from generation to generation within their groups,” study co-author and marine biologist Erick Higuera Rivas said in a press release.

Shark hunting pedigree

Higuera and his team recorded in their journal two hunts that took place two years apart. In the first attack in August 2020, five orcas chased a juvenile great white shark and knocked it over. Flipping a shark triggers a state called tonic immobility, which reduces its awareness of its surroundings. Marine biologists often turn sharks over to study them, because they are unlikely to bite or struggle in this state.

“This temporary state renders the shark defenseless, allowing orcas to extract its nutrient-rich liver and likely consume other organs as well, before abandoning the rest of the carcass,” Higuera explained. The shark’s enormous liver, which can account for up to a quarter of the fish’s total body weight, is full of nutrient-rich oils. The predatory group passed around the harvested organ, ensuring that even young calves were bitten.

The second hunt, seen in August 2022, also featured five orcas and followed the same pattern, suggesting that the orcas had learned that inducing tonic stillness could help them feast on the shark without getting bitten. The study authors suggest that orcas may also selectively target younger, naive sharks. Documented in South Africa, adult sharks flee areas where orcas are seen and do not return for months.

Only later did careful analysis of the orcas involved reveal that they belonged to Moctezuma’s group, which has now acquired a pedigree for hunting large sharks.

Changing temperatures provide opportunities for orca hunting

Researchers believe that warming water temperatures, driven by climate change and weather events like El Niño, may have pushed areas where sharks raise their young further into the Gulf of California, increasing hunting opportunities for orcas.

The authors add that this handful of isolated sightings is not enough to say with certainty whether orcas regularly hunt great white sharks or whether they only target young sharks opportunistically.

“Generating information about the extraordinary feeding behavior of killer whales in this region will allow us to understand where their main critical habitats are, so we can create protected areas and apply management plans to mitigate human impact,” said co-author Francesca Pancaldi of the Instituto Politécnico Nacional Centro Interdisciplinario de Ciencias Marinas in a press release.

Learn more: Instead of hunting in groups, orcas could attack great white sharks alone

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