In the sunlit waters of the Gulf of California, a showdown that rivals even the most famed WWE matchup has been apparently going down under our noses. A fascinating, yet unsettling behavior, the researchers who recently published that orcas here are hunting whale sharks, the world's largest fish. These predation events, documented between 2018 and 2024, reveal a coordinated and strategic approach by a pod of killer whales.
Whale sharks (Rhincodon typus) and orcas (Orcinus orca) are each remarkable in their own right. Whale sharks reach lengths of up to 18 meters (59 feet), yet despite their size, they are filter feeders (primarily consuming plankton, small fish, and krill). Found in warm, tropical oceans, these gentle giants are known for gathering in specific areas to feed, making these aggregation sites critical for their survival. Orcas are renowned for their intelligence and complex social behaviors. Found in oceans worldwide, they are highly adaptable hunters with a diverse diet that includes fish, seals, and even large whales. They live in close-knit family groups called pods, which often develop specialized hunting techniques tailored to their environment and prey.
The research, led by marine biologist Francesca Pancaldi of Mexico's Centro Interdisciplinario de Ciencias Marinas, describes how orcas employ a strikingly effective hunting method. "When hunting, all pod members work together, hitting the whale shark to turn it upside down. In that position the sharks enter a state of tonic immobility and can no longer move voluntarily or escape by going deeper," explained Erick Higuera Rivas, a marine biologist at Conexiones Terramar and senior author of the Frontiers in Marine Science article. "By keeping it under control, the orcas then have greater ease and speed in approaching the pelvic area of the shark and are able to extract organs of nutritional importance for them." It's thought the pelvic area has less muscle and cartilage, providing easier access to that tasty snack.
Or is it a snack? Interestingly, while the lipid-rich livers are thought to be the primary target of these attacks, there was no photographic evidence of the orcas consuming it. In fact, no photos have ever been taken of this happening. This raises questions about whether they might consume the liver out of sight or if the act of predation itself serves a different ecological purpose. While similar attacks on whale sharks may occur elsewhere, they have gone largely undocumented due to the difficulty of capturing such rare interactions. The researchers emphasized that collecting data on these events is challenging, as they are unpredictable, and image quality can often be too low to reliably identify the individuals involved. Identifying individuals is no small feat, as it requires analyzing photographs of dorsal fins and distinctive features like scars. One individual that has been ID-ed multiple times in the Gulf of California is a male orca nicknamed Moctezuma, identified in three of the four documented events. Alongside him, other pod members, possibly including a related female, were observed in the hunts, indicating a potential specialization in targeting whale sharks.
The implications this unique hunting pod here extend beyond the predation itself. Whale sharks are a draw for marine tourism in the region, and increased awareness of these predation events may necessitate stricter regulations to protect both species and their habitats. "There must be a specific regulatory norm that guarantees that any type of non-extractive use activity is carried out in a respectful and sustainable manner," Higuera Rivas said. With whale sharks visiting the Gulf of California during vulnerable stages of their life cycle, these attacks could also represent a significant threat to their population. And on the flip side, with climate change and other environmental pressures threatening marine ecosystems, the disappearance of whale sharks from the Gulf of California could pose significant challenges for this pod's survival.
Ultimately, new information related to these orcas helps researchers gain a greater understanding of their adaptations unique to their needs and geographical location. "It is very impressive how orcas work together strategically and intelligently to access only a very specific area of the prey. It highlights what great predators they are," concluded Higuera Rivas.