Researchers have documented unprecedented observations of orcas (Orcinus orca) systematically attacking and feeding on the livers of juvenile great white sharks in the Gulf of California, marking a significant new understanding of their hunting behavior. This first-of-its-kind study reveals a strategic and sophisticated predation technique, highlighting the orcas’ advanced intelligence and social learning.
A Clever Paralysis Technique
The orcas observed in the study employed a remarkable method to subdue their prey: they flipped the small sharks upside down, inducing a temporary state of paralysis known as tonic immobility. This phenomenon, also referred to as “brain freeze,” renders the shark defenseless, allowing the orcas to extract its nutrient-rich liver and potentially consume other organs before abandoning the rest of the carcass.
“This temporary state renders the shark defenseless, allowing the orcas to extract its nutrient-rich liver and likely consume other organs as well, before abandoning the rest of the carcass,” explains Jesús Erick Higuera Rivas, a marine biologist and director of the nonprofit research organization Conexiones Terramar.
The attacks were carried out off the coast of Mexico by Moctezuma’s pod, a well-known group distinguished by a large male with the same name. This pod previously gained attention last year for brutally killing a whale shark.
Previously Rare Behavior
While orcas are known to hunt great white sharks (Carcharodon carcharias) in regions such as South Africa and Australia, incidents in the Northeast Pacific are exceedingly rare. The last reliable sighting in this area was documented in 1997. Traditionally, orca attacks have focused on adult great whites, whose larger size provides a more substantial food source. There’s only one prior report of orcas killing a juvenile great white, an incident in 2023 off the coast of South Africa involving an orca named Starboard.
The recent observations, published in the journal Frontiers in Marine Science, suggest that the targeting of young great whites is more widespread than previously believed.
“This is the first time we are seeing orcas repeatedly target juvenile white sharks,” states Salvador Jorgensen, a marine ecologist at California State University, Monterey Bay. “Adult white sharks react quickly to hunting orcas, completely evacuating their seasonal gathering areas and not returning for months. But these juvenile white sharks may be naive to orcas. We just don’t know yet whether white shark anti-predator flight responses are instinctual or need to be learned.”
Three Observed Attacks
The study details three separate attacks on young great whites. Two of these occurred in August 2020, when five female orcas from Moctezuma’s pod relentlessly pursued one juvenile shark until it exhausted. They then flipped it onto its back, pushing it to the surface. The orcas forced the shark underwater, and upon resurfacing, they were observed holding its liver in their mouths. Soon after, the same group attacked and gutted a second young great white.
The third incident unfolded in August 2022 and followed a similar pattern. Five orcas, including one adult male, flipped a young great white onto its back, pushing it to the surface and biting it. Researchers noted that blood gushed from the shark’s gills and its liver protruded from its abdomen, enabling the orcas to grasp it.
Insights into Behavior and Future Research
The nature of the sharks’ injuries provides further support that tonic immobility plays a role in minimizing the risk of orcas being bitten while extracting the liver. Choosing juvenile prey also lessens the risk of injury for the orcas. However, it remains unclear whether orcas in the Gulf of California exclusively target young sharks or if they also regularly attack adults.
“This behavior is a testament to orcas’ advanced intelligence, strategic thinking, and sophisticated social learning, as the hunting techniques are passed down through generations within their pods,” Higuera Rivas noted.
A possible explanation for the recent observations is that great whites have only recently begun breeding in Mexican waters. Rising ocean temperatures and climate events such as El Niño are believed to have shifted the distribution of great white shark nurseries. Moctezuma’s pod is likely capitalizing on the increased number of juveniles present in the Gulf of California.
Ultimately, this research provides valuable insights into the complex interactions within marine ecosystems and raises important questions about the adaptability of both orcas and great white sharks. Further research is needed to fully understand the long-term impacts of this predation pattern on white shark populations and the broader marine environment.
