SCI-TECH

The recent autopsy of a partially devoured great white shark confirms a brutal hunting trend—killer whales around the world are not afraid to attack the fearsome fish, especially when they get a taste for liver.

Great white sharks are apex predators, but that doesn’t mean they’re invincible. In October 2023,  the remains of a Carcharodon carcharias washed ashore in southeastern Australia showing clear evidence of having been attacked by an unknown species. The carcass featured four distinct bite wounds around its underside, and notably lacked its liver, digestive, and reproductive organs. Researchers identified their suspect almost immediately, but hesitated to offer a definitive answer before conducting a postmortem investigation.

According to their results recently published in the journal Ecology and Evolution, the culprit is clear: a killer whale fatally assaulted the over-15-foot-long shark, then proceeded to devour its innards. While it most likely zeroed-in on the nutrient-rich liver, multiple scavengers also got in on the meal.

“Swabs were taken from bite wounds on the white shark and sequenced for remnant genetic material from the shark’s predator,” Isabella Reeves, study lead author and a PhD candidate at Flinders University’s Southern Shark Ecology Group and the West Australian Cetacean Research Center (CETREC), said in an accompanying statement. “We were able to confirm the presence of killer whale DNA in the primary bite area, while the other three wounds revealed DNA from scavenging broadnose sevengill sharks.”

The wildlife forensic analysis supported eyewitness statements from 2023. Two days before the great white washed ashore, multiple local beachgoers reported seeing killer whales (including local legends “Bent Tip” and “Ripple”) hunting down an unknown “large prey” target in Australia’s Bridgewater Bay. But this isn’t the first time researchers have documented killer whales attacking great white sharks.

According to Reevers and her colleagues, similar situations of cetaceans “specifically targeting the liver” were previously seen off the coasts of South Africa and California. While experts theorized similar feeding patterns may also occur around Australia, they lacked direct evidence until the postmortem.

“These findings provide compelling evidence of killer whale predation on white sharks in Australian waters, with a strong indication of selective liver consumption,” said Reeves. “This suggests that such predation events may be more widespread and prevalent across the globe than previously believed.”

For the moment, however, it remains unclear just how much these hunting parties may affect Australia’s oceanic ecosystem. 

“We don’t know how frequently these events occurred in Australian waters and therefore how significant these findings are,” added Adam Miller, a study senior author and ecologist at Cesar Australia.

Given the effects in South Africa and California, it’s possible such attacks have substantial ripple effects. Miller explained that current evidence suggests fewer great white sharks (regardless of being either chased away or eaten) “has led to cascading shifts in the wider marine ecosystem.”

“We know that white sharks are key regulators of ecosystem structure and functions, so it’s very important we preserve these top predators,” he added. “Therefore, it is important that we keep a tab on these types of interactions in Australian waters where possible.”

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