Study Reveals New Information About Killer Whales Hunting Great White Sharks
Scientists always knew great whites were part of the orca's diet. Drone footage from South Africa finally confirmed it
Orcas and great white sharks have long duked it out for a top spot in the ocean food chain. Based on size alone, we can feel pretty comfortable giving orcas the title, since the average orca weighs upwards of 7,000 pounds while female great whites (which dwarf their male counterparts) top out at around 5,000 pounds.
This disparity in size isn’t the only proof of orca superiority. Scientists have long accepted that orcas prey on great whites and other shark species based on tourist accounts and washed-up carcasses with livers and other organs expertly removed. However, no one has ever documented direct predation on aerial video before.
That changed on the afternoon of May 16, 2022, when a hobbyist drone pilot flew a drone over a group of five killer whales near Hartenbos Beach on the southern coast of South Africa. The drone filmed one of the orcas pushing a 9-foot-long shark carcass to the surface of the water near two other orcas. The three whales then began to feast on the shark’s organs. Around the same time, a separate helicopter flying tourists over the area witnessed the same orcas killing two great white sharks. One of them eventually ate a floating shark liver “roughly the size of the killer whale’s head.” The pilots took cell phone pictures and videos of the event, but this footage wasn’t released until long after the drone video came out in June.
A new study, published in Ecology on Oct. 4, advances marine biologists’ understanding of how these two apex predators interact and how great white sharks evade predation—something they aren’t forced to do very often.
“This was only part of an hour-long hunt of multiple sharks, as revealed by the exclusive helicopter footage,” a press release from Phys.org says. “The new paper offers more extensive footage, along with data from tags, drone surveys and shark-tour boats showing that white sharks fled from the Mossel Bay region of South Africa for several weeks.”
According to the study, the footage recorded from the helicopter shows the hunted sharks swimming in tight circles around the orcas. This is apparently the same technique that seals, turtles, and other prey species have exhibited when being hunted by great whites.
“However, because killer whales are social and hunt in groups, this evasive tactic may not be effective,” the study’s authors point out.
Two of the five orcas in the feeding pod were identified as “Starboard” and “Port,” and they’re well-known to area biologists. When a swarm of dead sharks washed up on the beaches of South Africa in the mid 2010s, these two were documented as the culprits. Each has a collapsed dorsal fin, one to the left and one to the right, which helps explain the clever names. Now that researchers have finally caught them in the act, they can uncover more secrets about their hunting strategies and how they impact great white shark populations.
“This behavior has never been witnessed in detail before, and certainly never from the air,” lead author Alison Towner, a senior shark scientist at Marine Dynamics Academy in Gansbaai, South Africa, tells Phys.org.