Over four days in early May, three dead great white sharks washed ashore in South Africa—with their livers missing. Researchers with the Dyer Island Conservation Trust did necropsies and came to the conclusion that, based on the sharks' injuries, orcas likely killed them and ate their livers, the researchers write on the Marine Dynamics blog. In the case of one of the sharks, the heart was also eaten. As LiveScience explains, it's not unprecedented for killer whales to hunt great whites, but it's also not known to be typical.
Orcas are known, however, to hunt broadnose sevengill sharks and eat their livers, and other marine mammals—including sea lions—are known to hunt smaller sharks and eat their livers and other organs, leaving the rest of the carcass behind. What's so appealing about the liver? Sharks don't have a swim bladder to keep them buoyant, so they have "very large" livers that are filled with fats to give them buoyancy, a biologist explains. The livers are also "very energy- and nutrient-rich," he says. As Newsweek explains, they also contain high levels of squalene, a hydrocarbon used to produce steroids and hormones.