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Two killer whales hunt and eat great white sharks, new research finds.
A recent article in African Journal of Marine Sciences focuses on two killer whales that researchers have spotted hunting great white sharks off the coast of South Africa. The whale pair’s appetite for great whites has prompted the sharks to flee the area.
“Initially, after an orca attack in Gansbaai, individual great white sharks would not show up for weeks or months,” the article’s lead author Alison Towner told SWNS.
“It reflects what we are seeing from wild dogs in the Serengeti in Tanzania in response to the increasing presence of lions,” she added. “The more often the orcas visit these places, the longer the great white sharks stay away.”
According to the article’s findings, eight great white sharks with identifiable orca bite marks have washed up dead on the South African coast since 2017.
Seven of these sharks had their livers removed by the whales during the attack, and some had their hearts removed as well. All of the dead sharks found had distinctive wounds that could be traced back to the same pair of killer whales.
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Researchers believe the orcas killed more than the eight great whites that washed ashore and that other killer whales are capable of similar attacks.
Orcas are the only predator of the legendary great white shark – apart from humans. The whales can grow up to 30 feet long and weigh over six tons – they feed on fish, squid, seals and seabirds. Great whites can grow up to 22 feet long and weigh around 2.5 tons.
Towner, a Ph.D. A student at Rhodes University in Makhanda, South Africa, said this research is “particularly important” because it determines “how large marine predators respond to risk.”
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She added that the research could also help scientists understand the “dynamics of coexistence” between “other predatory communities.”
Towner’s recently published study used long-term sighting and tagging data to show that the two orcas scared great whites away from South Africa’s Gansbaai coast, which sharks had dominated for years. Located 60 miles east of Cape Town, Gansbaai was known for great white sightings.
Towner, a senior biologist at Dyer Island Conservation Trust off the southern tip of Africa, who lives in Gansbaai, has witnessed firsthand how the two shark-hunting orcas drove the area’s great whites out and transformed the marine ecosystem.
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“It has triggered the emergence of a new mesopredator in the area, the bronze whaler shark, which is known to be eaten by great whites,” she explained.
“Balance is crucial in marine ecosystems. For example, since no great white sharks restrict Cape fur seal behavior, the seals may eat critically endangered African penguins or compete for the small pelagic fish they eat,” Towner added.