Marine biologist Dr Alison Kock said the orcas had only eaten livers of the broadnose sevengill sharks, a strange practice she’d observed in the pair for eight years.
“At least 17 sevengill sharks have been killed by infamous killer whale pair Port and Starboard this week in South Africa,” Kock said on Twitter.
“Only the livers were eaten with the leftover carcasses washing ashore.
“We first observed this pair hunting sevengill sharks in False Bay, Cape Town in 2015 … the drama didn’t stop there.
“In 2017, this pair then started targeting great white sharks, ultimately resulting in the sharks abandoning established aggregation sites.”
Kock explained orcas learn from experimenting with prey and can “remember” specific types of foods that they can then continue to hunt.
“They likely initially learn by experience when first predating a new species,” she said.
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This means that once the orcas are aware of the liver’s location on a shark, “they will remember it forever and become more efficient”.
Shark livers are highly nutritious and contain large levels of fats and vitamins.
“Orcas may have learned that consuming shark livers provides high energy and nutrients,” Kock told Live Science.
“Sharks’ livers are large and buoyant, and they float to the surface of the water when a shark is killed.
“This makes them easy for orcas to spot and access, compared to other organs that may sink to the bottom or be harder to locate.”
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