Whale sharks frequent aggregation sites in the Gulf of California, especially in their younger and smaller stages, making them more susceptible to predators. Anecdotal evidence has suggested orcas might target these giant fish, and now researchers in Mexico have documented four distinct predation events involving orcas and whale sharks.
"We show how orcas displayed a collaboratively hunting technique on whale sharks, characterized by focusing on attacking the pelvic area causing the whale shark to bleed out and allow orcas access to the lipid-rich liver," said Erick Higuera Rivas, a marine biologist at Conexiones Terramar and senior author of the Frontiers in Marine Science article. "One individual was engaged in three of the four events, alongside with other members who might belong to a pod specialized on hunting on sharks."
Observations of Specialized Hunting Behavior
The observed predation events took place between 2018 and 2024 in the southern Gulf of California, documented through public and scientific images and videos. Orcas were identified using photographs of their dorsal fins and unique markings, such as scars.
In three of the four recorded hunts, a male orca named Moctezuma was present. A female orca, previously spotted with Moctezuma, participated in one event, suggesting a familial or pod-based connection.
"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," Higuera Rivas explained. "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."
This technique appears to target the ventral side of the whale shark, thought to be its least protected area due to thinner muscle and cartilage layers, making access to critical organs like the aorta easier. Although orcas are known to consume whale sharks' livers, no photographic evidence confirmed this during the observed events.
Implications for Orca Behavior and Conservation
The documented behavior suggests that certain orcas in the Gulf of California have developed unique adaptations for hunting whale sharks. This may reflect a broader but underreported phenomenon in other regions, according to the researchers.
Collecting such data proved challenging due to the unpredictability of attacks, limited access to imagery, and the often poor quality of available photos and videos. Despite these hurdles, the findings highlight the ecological and behavioral intelligence of orcas.
"The fact that there is a whale shark hunting pod in the Gulf of California increases the need for managing marine adventurers and tourists," Higuera Rivas noted. "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."
Additionally, the pod's reliance on whale sharks could make them vulnerable to the impacts of climate change, which may affect the availability of their prey in the region.
Understanding these orcas' unique adaptations sheds light on how they navigate their environment and prey on specific targets. "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," Higuera Rivas concluded.
Research Report:Orca whales (Orcinus orca) hunt, kill, and consume the largest fish on Earth, the whale shark (Rhincodon typus).
Related Links
Frontiers
Follow the Whaling Debate
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
