A groundbreaking study has revealed that orca pods in the Pacific Ocean off Mexico’s coast have developed an ingenious hunting strategy to target whale sharks, the world’s largest fish. While it was previously speculated that orcas could prey on these massive sharks, the behavior had never been documented in detail—until now. Researchers captured four separate hunting events from 2018 to 2024, providing clear evidence of how orcas are able to subdue and kill these giant creatures.
The hunts typically involve young whale sharks, ranging from 3 to 7 meters (10 to 23 feet) in length, making them more vulnerable to the orcas’ predation. Although whale sharks can grow up to 18 meters (60 feet) in length, their size doesn’t necessarily confer an advantage when confronted by a pod of skilled orcas.
“The whale shark has the smallest brain relative to body mass, and its brain is only about the size of an egg,” said Francesca Pancaldi, the study’s lead author and a researcher at Centro Interdisciplinario de Ciencias Marinas in Mexico. “It’s a slow-moving fish with tiny teeth that don’t serve as a defense mechanism.”
The study, published in Frontiers in Marine Science, detailed the orca pod’s methodical approach to hunting the whale sharks. By using their bodies to strike the sharks at high speed, the orcas are able to flip them upside down, a maneuver known as tonic immobility, where the shark becomes temporarily paralyzed in fear. Once the whale shark is immobilized, the orcas target its abdomen, allowing blood to drain from the shark before consuming its internal organs.
A Unique and Powerful Hunting Technique
The study showed that orcas work together as a coordinated group during these hunts. One orca will strike the whale shark on its belly, while others may target the shark’s head, systematically flipping it over. This cooperative approach makes it easier for the orcas to overpower their prey, despite the shark’s massive size.
The researchers speculate that the orcas are particularly interested in the whale shark’s liver, which is rich in nutrients and constitutes a large portion of the shark’s body weight, although they did not directly observe the orcas consuming this organ.
Sarah Teman, a doctoral student at the University of Washington, commented on the importance of the finding: “This is the first time we’ve clearly documented orcas hunting whale sharks, and it’s exciting because it showcases the adaptability of orcas in targeting the world’s largest sharks.”
Orca Behavior and Ecological Impact
Orcas are known as apex predators of the ocean, preying on a wide range of marine creatures, including fish, seals, dolphins, and even other sharks. While there is only one species of orca, different ecotypes or groups exhibit distinct behaviors based on their prey preferences. The Gulf of California orcas might represent a new ecotype that specializes in hunting elasmobranchs—sharks and rays.
Moctezuma, an 8-meter (26-foot) male orca, is one of the key hunters in this pod and has been observed targeting other elasmobranch species, such as Munk’s pygmy devil rays, bull sharks, and stingrays. The study authors suggest that further research is needed to confirm whether these Gulf of California orcas could be classified as a new ecotype.
Interestingly, in other parts of the world, orcas have also been observed developing unique techniques to hunt great white sharks. In South Africa, this behavior has had an ecological impact, as the presence of orcas has driven great white sharks away from some coastal areas. However, the researchers in Mexico do not believe that orcas’ predation on whale sharks has caused any significant harm to their population or the wider ecosystem in the Gulf of California.