DNA Confirms Orcas Prey Upon One of Australia's Deadliest Marine Predators
Nature

05 February 2025
ByMichelle Starr


Orca's taste for shark livers confirmed in new study. (slowmotiongli/Getty Images)

It's not just the white sharks off the South African coast of Gansbaai that feel the deep, primal fear known only to prey. ... For years now, a single pair of orcas (Orcinus orca) has been recorded off the coast of Gansbaai, harrying and hunting the white sharks (Carcharodon carcharias) that make the area one of their homes, slurping out the sharks' nutrient-rich livers, leaving the rest of the carcasses to wash ashore.

It now appears that the behavior is more widespread than we knew. In 2023, off the southeastern coast of Australia, half a world away from Gansbaai, the remains of a 4.7-meter (15.4-foot) white shark washed ashore, a gaping hole in its abdomen ringed by ragged tooth marks, and a marked absence of a liver.

DNA sequencing has now confirmed that the culprit was none other than an orca.


The DNA evidence of the orca attack was found in the bite marks on the shark's carcass. (Ben Johnson, Portland Bait and Tackle)

"There were four distinctive bite wounds, one of which was characteristic of liver extraction by killer whale, similar to what has been observed in South Africa," says biologist Isabella Reeves, of Flinders University in Australia.

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