Something odd is going on off the shores of South Africa. Several deceased great white sharks are turning up along a stretch of coastline with their livers quite precisely removed from their carcasses; two of them were also missing their hearts.

After a brief bit of sleuthing by marine conservationists, the finger was pointed squarely at orcas. Now it appears they have struck again: a fourth great white has been found lacking its liver on the same stretch of coastline. Once again, the organ was removed with “surgical precision”.

The autopsy was carried out once again by the Dyer Island Conservation Trust team, led by White Shark biologist Alison Towner. In a Facebook post, Marine Dynamics explain that the carcass of a male was found on June 24 in a relatively fresh state of decomposition. It was missing not just its liver, but its stomach and testes too – and it bled out profusely before dying.

The carcass this time was 4.1 meters (13.5 feet) long, which is remarkably the third largest of the four murder victims that have appeared recently. The most massive was a 4.9-meter (16-foot) female shark, and took the ignominious award of being the largest shark ever dissected in South Africa.

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Incredibly, the culprits weren’t just identified by the type of wounds located on the victim – they were seen actively patrolling the scene of the crime before fleeing the area.

“The pair of orcas believed to be responsible were sighted offshore of Danger Point then again in Franskraal today,” the Facebook post reads. “Marine Dynamics cage diving boat tracked the pair. Subsequently, all cage diving boats failed to see white sharks today and it is believed the sharks may have fled the area once again.”

This murderous pattern began in early May, and the latest killing suggests that it’s likely to continue for some time. Although orcas are effective hunters, it’s somewhat unusual that they’re going after great whites, who are the unquestionable apex predators in these waters.

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There are various hypotheses being banded about trying to explain why these orcas are eating select organs of the great white, rather than the whole carcass.

As we noted previously, the specificity of the organ harvesting isn’t too unusual – when hunting whales, orca sometimes kill their calves and only eat their tongues. Some organs provide a lot more energy than the rest of the flesh, so perhaps this type of feasting is a form of energy conservation.

Orcas would expend a lot of energy just killing a great white shark in the first place though, so this idea may be invalid.

In any case, their precise removal of these organs from a thrashing great white is as mysterious as it is unprecedented.