A pair of orcas off the coast of South Africa specialize in hunting sharks to extract their livers while leaving other parts intact.
The carcass of a shark with its liver extracted washed up on the beach. (Photo: Marine Dynamics Academy)
The two orcas, named Port and Starboard by marine conservationists, are disrupting the food chain in the waters off Cape Town, leading to a decline in the great white shark population. Last week, researchers from the Marine Dynamics Academy discovered a total of 17 shark carcasses in a single day. They have been monitoring the hunting habits of Port and Starboard since their arrival in the area in 2015. Each shark carcass was found torn apart and missing its liver, a nutrient-rich organ favored by orcas.
The team of experts believes that Port and Starboard specifically target livers because they contain high levels of squalene, a compound that plays a crucial role in hormone production. The orcas can extract the liver from sharks with remarkable precision. Working together, the pair of orcas drive the sharks to the surface, flipping them over before biting into their bellies to retrieve the liver. Other internal organs of the sharks remain intact.
Orcas, the only predator that preys on great white sharks, are extremely intelligent and skilled hunters. In addition to sharks, they also hunt seals, dolphins, turtles, and squid. The bold hunting skills of Port and Starboard in South Africa have allowed researchers to observe the flight responses of sharks. A study published in October 2022 indicated that terrified sharks avoid returning to their natural hunting grounds due to the threat posed by the orcas’ slaughter.
“For the first time, we observed the escape response of great white sharks in the presence of the two orcas, Port and Starboard, in False Bay in 2015 and 2017. Sharks abandoned their previous habitats, significantly impacting both the ecosystem and related tourism activities,” said Dr. Alison Kock, a shark specialist at South African National Parks.
Previous research has noted that new behaviors spread among orcas over time through cultural transmission. The research team hopes their findings can help develop better conservation measures for great white sharks. The global shark population has declined by over 70% in just 50 years.
