Scientists have observed a lone orca killing a great white shark for the first time.
Spotted in Mossel Bay, South Africa, the whale tore off the shark’s left pectoral fin, killing the animal in under two minutes. The mammal, named Starboard, then ate the shark’s liver, researchers reported Friday in the African Journal of Marine Science.
“Starboard’s predation strategy here really surprised us,” Alison Towner, first author of the new study and a shark expert at Rhodes University in South Africa, tells National Geographic’s Jessica Taylor Price. “Previously, we observed him hunting near others, noting teamwork in securing white sharks and accessing their livers.”
“While killer whales can hunt large prey individually, this is the first documented instance in South Africa involving white sharks as prey,” Towner tells Scientific American’sStephanie Pappas. “The surprising element was how quickly the killer whale immobilized and consumed the liver of the shark.”
Killer whales are highly social and live in pods. Like a pack of wolves, they use a coordinated hunting strategy, working together to catch prey. Sometimes, an orca will hunt alone, but until now, one had never been documented taking down a white shark singlehandedly.
Starboard has a companion, named Port—the two male orcas are named after the directions each of their dorsal fins bend. The pair had previously gained notoriety for hunting together and preying on sharks, as well as tearing out and eating shark livers.
These livers are highly nutritious. “Shark livers are packed with rich, oily lipids, making up to one third of their body mass in some species,” Towner tells Live Science’s Melissa Hobson.
But as beneficial as this might be for the orcas, Port and Starboard’s predation has led to the displacement of a number of shark species, according to the new paper. A 2019 study found that white sharks will flee an area when killer whales are nearby.
Orcas have also been observed working in groups to push animals off ice floes, kill a bowhead whale and even take down a blue whale, writes National Geographic.
On June 18, 2023, a vessel left shore to observe Port and Starboard, as the orcas had been reported in the area earlier that afternoon. Scientists found the water’s surface seemed to be slick with shark liver, a sign that a shark had already been killed.
“Shark liver has a unique and recognizable scent—oily,” Towner tells Scientific American. “Once you’ve encountered it, you won’t mistake it for anything else.”
Then, the researchers spotted Starboard chasing after a young white shark, while Port stayed more than 100 yards away. The hunting orca pulled the fin from the shark, and just moments later, people on a second vessel saw Starboard with a bloody piece of peach-colored shark liver in its mouth.
Luke Rendell, a marine mammal scientist at the University of St. Andrews in Scotland who did not contribute to the findings, tells BBC News’ Victoria Gill that the report was “a really beautiful observation” of the hunting behavior. “It’s interesting that it’s just one animal.”
The juvenile shark was only about eight feet long and might have been an easier target as a result. To hunt adult white sharks, which can reach more than 21 feet in length, orcas might have to work together, the study authors write.
Researchers are also still trying to determine how exactly the killer whales manage to open up the white sharks and get at their livers.
The shark’s death was a blow to some researchers. “After 24 years of working with the great white, to see an orca—that, before [this], I loved a lot—killing my preferred shark, I was really stressed, is the minimum that I can say,” Primo Micarelli, a marine biologist at the University of Siena in Italy who witnessed the event and co-authored the study, tells Scientific American.
Though overfishing and other human activities are most damaging to white shark populations, the added pressure of predation by orcas could impact the species’ numbers around South Africa. Following the attack, white sharks left the area for about four months, Towner tells National Geographic. And changes to the region’s white sharks could bring cascading effects through the ecosystem.
“Despite my awe for these predators, I’m increasingly concerned about the coastal marine ecology balance,” Micarelli tells the Guardian’s Nicola Davis.
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