Orcas are ganging up on great white sharks to eat their livers

Orcas in the Gulf of California have been hunting juvenile great white sharks using a clever tactic: flipping them upside down to render them immobile. The discovery suggests there may be a previously unrecognised group of orcas in the region that specialises in hunting sharks.

Only a few orca populations are known to feed on sharks, and even fewer have been found to eat great whites (Carcharodon carcharias). For example, orcas (Orcinus orca) off the coast of San Francisco were documented killing a great white in 1997, and a great white carcass near Australia showed signs off an orca attack in 2023. But until recently, there had only been one known instance, recorded in South Africa, of the animals preying on juvenile great white sharks.

Jesús Erick Higuera-Rivas, an independent marine biologist in Mexico, and his colleagues captured video footage of orcas in the Gulf of California hunting juvenile great white sharks on two separate occasions. The first, recorded in August 2020, showed five female orcas working together to push a young great white to the surface. “The orcas were ramming the great white to flip it upside down,” says Higuera-Rivas.

The manoeuvre forced the shark into a state of temporary paralysis, called tonic immobility. It also allowed the orcas to get at the shark’s energy-rich liver, which they shared amongst themselves. A few minutes later, the pod repeated the attack on a different adolescent great white. In August 2022, the research team recorded another group of five orcas using the same technique to hunt a young great white around the same location at the same time of year.

The researchers identified some of the orcas in the first incident as those previously spotted hunting whale sharks and bull sharks. Footage from the second incident wasn’t clear enough to determine whether these orcas belonged to the same pod. “But it is highly possible,” says Higuera-Rivas.

Orca populations drastically differ depending on where they are located. “Orcas are hunting machines. They are like snipers – they use specific hunting strategies, very specific ones depending on their prey,” says Higuera-Rivas. These findings suggest the orcas belong to a previously unrecognised shark-eating group, he says.

“So now we have an example of another unique feeding strategy that probably isn’t shared by any other group of [orcas] in the world,” says Andrew Trites at the University of British Columbia in Canada. However, more research is needed to know for sure, as the orcas could be an offshoot of those from the Pacific Northwest that hunt other types of sharks, he says.