Orcas, or killer whales, are the apex predator in the ocean when they work together.
A new study documents how a pod of orcas is able to hunt and kill the largest fish in the world, the whale shark (Rhincodon typus), which can be twice the size of an individual orca (Orcinus orca), though the pod most often targets smaller, juvenile sharks.
Anecdotal observations in Mexico’s Gulf of California found that orcas appeared to prey on whale sharks. However, the behavior wasn’t well understood or scientifically recorded until recently, when between 2018 and 2024, a team of researchers recorded videos and photos of the same pod of orcas successfully hunting and killing whale sharks on four separate occasions.
“In all the events that we have registered since 2018, it’s been always the same pod, the same individuals, the same members of this orca family,” marine biologist Erick Higuera Rivas, study co-author from Conexiones Terramar, a conservation science NGO in Mexico, told Mongabay by phone.
Several members of the research team were in the water for other research purposes along with tourists with video cameras when they happened to observe the orcas’ whale-shark-hunting strategy. They saw the orca pod work together to keep the whale shark near the water’s surface, after which they flipped the shark upside down, causing it to go into a state of tonic immobility, or temporary inactivity. Once rendered unable to move, the orcas bit and tore at the shark’s belly to get to its lipid-rich liver.
“The liver of sharks is very big, it’s a very big organ,” Francesca Pancaldi, the study’s lead author and marine biologist at WWF, told Mongabay by phone. “It’s very fatty, has a lot of nutrients. And it’s very important for the orcas to consume that because it provides a lot of calories for them.”
Once the orcas have the prize liver, the family eats together.
“When they feed, they share food between the individuals of the pod. [They even] pass a piece of shark from one individual to another,” Pancaldi said.
In this way, the youngest members of the pod develop a taste for whale shark liver, she added. By observing the hunt, they also learn the process of carrying out this complex behavior from their elders. Flipping over an animal potentially much larger than themselves to access a very specific part of its body isn’t an instinct, but a learned behavior that requires coordination and skill, passed down through generations, Pancaldi said.
Banner image of a whale shark being brought to the surface as an orca bites near the pelvic area, courtesy of Kelsey Williamson.
Credits
