Scientists Document Orcas Hunting White Sharks in Breeding Area for First Time

For the first time, scientists have documented orcas hunting white sharks in a nursery area. Additionally, warming waters in the region may be altering the zones where these pups develop. 'I think that orcas that eat elasmobranchs — sharks and rays — could hunt white sharks anywhere they wanted,' explained marine biologist Erick Higuera Rivas, a co-author of the study. 'This behavior reflects the advanced intelligence of orcas, their strategic thinking, and their social learning ability, as these techniques are passed down between generations,' he added. During the study, scientists documented two hunting events in which orcas killed three white sharks. The first attack, recorded in August 2020, involved five orcas chasing a shark pup. They worked together to push it to the surface and then flip it over, a maneuver known to induce a condition called tonic immobility, which paralyzes the shark by altering its perception of its environment. Once immobilized, the orcas took it underwater and reappeared with its liver in their mouths. A second attack was observed shortly after, using the same technique. In August 2022, a similar case was recorded: an orca was seen flipping a white shark pup and extracting its liver. However, these white shark pups may not yet recognize orcas as a threat. 'We still don't know if the flight response to predators in white sharks is instinctive or must be learned over time,' the researcher added. The researchers also suspect that climate phenomena like 'El Niño' may have altered the white sharks' breeding areas, increasing their presence in the Gulf of California. 'Adult white sharks react quickly to the presence of hunting orcas: they completely evacuate their seasonal gathering areas and do not return for months,' explained Salvador Jorgensen, a co-author of the study and a researcher at California State University. Until now, orcas had only been seen hunting adult white sharks in South Africa, where a single prey was enough to feed the entire pod. The orcas were observed eating the shark's liver. Flipping a shark onto its back induces a state known as tonic immobility, which paralyzes it by altering its perception of the environment. This temporary state leaves the shark completely helpless, allowing the orcas to obtain its liver—highly nutritious—and probably consume other organs before abandoning the rest of the body, Rivas concluded. The latest findings indicate that orcas may have developed a specialized technique to induce this state of immobility, reducing the risk of being bitten by the sharks. They used a technique to flip them over, immobilize them, and extract their liver, suggesting a possible seasonal shift in their diet. Until now, orcas had only been seen hunting adult white sharks in South Africa, where a single prey was enough to feed the entire pod. However, a team of researchers recorded in the Gulf of California a group of orcas employing a specialized technique to hunt white shark pups: they flipped them, paralyzed them, and extracted their liver to share among the group members. According to the study, published in the journal 'Frontiers in Marine Science,' these orcas—nicknamed the Moctezuma pod—may be taking advantage of the local presence of a shark nursery, with younger, less experienced, and easier-to-catch sharks. These orcas may also be taking advantage of the effects of water warming in the Gulf of California, which is suspected to be altering the sharks' breeding zones, according to the researchers. This exposes them to this pod of orcas, and each new generation of pups could become a seasonal, vulnerable target. The researchers conclude that future work will need to continue monitoring changes in the distribution and concentration of white shark pups driven by ocean warming.