Orcas, also known as killer whales, and great white sharks are apex predators whose interactions have long captivated scientists. Understanding their relationship sheds light on complex marine ecosystems and the intricate dynamics of top predators. This article explores confirmed instances of orcas hunting great white sharks.
The Unmistakable Reality
Orcas indeed hunt and kill great white sharks, a fact now firmly established by scientific observation. Since 2017, increasing evidence, including drone footage and analysis of shark carcasses, has documented multiple instances off the coast of South Africa. Carcasses often wash ashore missing specific organs. Similar predation events, confirmed by DNA analysis, have also been recorded in Australian waters, indicating a more widespread occurrence than previously thought. May 2022 drone and helicopter footage provided unprecedented visual confirmation of these hunts, offering detailed insights into orca behavior.
The Strategic Target: Shark Liver
A primary motivation for orca predation is the high nutritional value of the shark’s liver. This exceptionally large organ constitutes between 5% and 25% of a shark’s total body weight and up to 90% of its body cavity. Shark livers are rich in fats and squalene, a highly caloric oil that provides a significant energy source for the orcas. Orcas demonstrate remarkable precision in extracting these livers, sometimes leaving the rest of the carcass. This selective consumption suggests the liver provides a concentrated boost of energy and nutrients that meets the orcas’ dietary needs.
Coordinated Hunting Techniques
Orcas employ sophisticated and coordinated hunting strategies to subdue great white sharks, showcasing their intelligence and teamwork. One common tactic involves ramming the shark to stun or disorient it, or using powerful tails to slap and incapacitate prey. A particularly effective method involves flipping the shark upside down, which induces a state known as tonic immobility. In this trance-like state, a shark becomes paralyzed and vulnerable, allowing the orcas to safely access its liver. While group hunting is typical, individual orcas, like “Starboard” in South Africa, have also been observed successfully extracting a great white shark’s liver in as little as two minutes.
Sharks’ Avoidance Response
The presence of orcas triggers a profound avoidance response in great white sharks, leading to significant behavioral changes and shifts in distribution. Following orca attacks, great white shark populations in certain areas rapidly vacate traditional hunting grounds. For example, after an orca attack in Gansbaai, South Africa, individual great white sharks did not appear for weeks or even months. Data from tagged sharks in areas like the Southeast Farallon Islands off California and Gansbaai show that sharks abandon these sites entirely when orcas are present, sometimes for extended periods, even up to a year. This demonstrates the profound impact orcas have on great white shark behavior and their distribution within marine ecosystems.