Orcas seen killing young great white sharks by flipping them upside-down

A pod of orcas specializing in shark hunting in the Gulf of California has been filmed expertly targeting young great white sharks, turning them upside down to eat the energy-rich livers.

The group, known as the Moctezuma pod, could take advantage of warming waters that are changing shark breeding grounds to prey on juveniles, which don’t have the experience to flee like older sharks do. These observations suggest that orcas may hunt white sharks more often than we thought. However, a larger survey collecting more data is needed to draw strong conclusions.

“I believe that orcas that feed on elasmobranchs – sharks and rays – could eat a great white shark, if they wanted, wherever they went looking for one,” said marine biologist Erick Higuera Rivas, project director at Conexiones Terramar and Pelagic Life and lead author of the paper in Frontiers of Marine Science.

“This behavior demonstrates the advanced intelligence, strategic thinking and sophisticated social learning of orcas, as hunting techniques are passed down from generation to generation within their groups.”

Predators become prey

Scientists spotted two hunts, killing three white sharks, during routine orca monitoring. They recorded the hunts in detail, identifying the individual orcas involved by the characteristics of their dorsal fins.

During the first hunt, in August 2020, five orcas were seen chasing a young white shark. They pushed him to the surface and worked together to knock him down.

Eventually, they took him underwater and reappeared with the shark’s liver in his mouth. Shortly after, they did the same with a second juvenile shark.

A second hunt, observed in August 2022, followed a similar pattern: five orcas pushed a young white shark onto its back and brought it to the surface. The shark was bleeding from its gills and its liver was visible. Orcas have been seen eating it.

Flipping a shark in this way induces a state called tonic immobility, altering the shark’s awareness of its surroundings in a way that paralyzes it.

“This temporary state renders the shark defenseless, allowing orcas to extract its nutrient-rich liver and likely consume other organs as well, before abandoning the rest of the carcass,” Higuera explained.

By examining the sharks’ injuries, scientists believe that the orcas may have developed a specialized technique to induce this condition, thereby minimizing the risk of being bitten. It might be easier to do this with smaller (and therefore younger) great white sharks, or less experienced juveniles might be easier prey.

“This is the first time we’ve seen orcas repeatedly target juvenile white sharks,” said Dr. Salvador Jorgensen of California State University, an author of the paper.

“Adult white sharks respond quickly to orca hunting, completely evacuating their seasonal staging areas and not returning for months. But these young white sharks may be naive toward orcas. We simply don’t know yet whether white sharks’ flight responses from predators are instinctive or must be learned.”

After identification, the pod of orcas was found to be one called the Moctezuma pod, named after a prominent member of the pod. This group has previously been seen hunting rays as well as whale and bull sharks, and may have learned from their experience how to prey on great white sharks.

Change range, change diet?

Changes in the distribution of white sharks in the Pacific may have provided an opportunity for Moctezuma’s group. Climatic events like El Niño appear to have altered white shark breeding grounds and increased their presence in the Gulf of California, which could mean they are more exposed to this group, and each new cohort of juveniles could be a vulnerable seasonal target.

However, these are just observations. The scientists plan to follow up with a detailed study of the diet of this population of orcas, which would help determine whether they regularly hunt white sharks or concentrate on juveniles when they are available. However, this will not be easy: field work is expensive and orca hunts are unpredictable.

“So far we have only observed this pod feeding on elasmobranchs,” said co-author Dr. Francesca Pancaldi of the Instituto Politécnico Nacional Centro Interdisciplinario de Ciencias Marinas.

“There could be more. Generating information about the extraordinary feeding behavior of killer whales in this region will allow us to understand where their key critical habitats are, so we can create protected areas and implement management plans to mitigate human impact.”