In 2009, the team tagged 17 great whites, which spent months circlingSoutheast Farallon Island and picking off the local elephant seals. But this period of steady hunting ended on November 2 of that year, when two pods of killer whales (orcas) swam past the islands in the early afternoon. In the space of eight hours, all 17 great whites abruptly disappeared. They weren’t dead; their tags were eventually detected in distant waters. They had just fled from Farallon. And for at least a month, most of them didn’t return.
Orcas have a friendlier image than great white sharks. (Perhaps because of their respective portrayals in movies: Jaws 2 even begins with the beached carcass of a half-eaten orca.) But orcas are “potentially the more dangerous predator,” says Toby Daly-Engel, a shark expert at the Florida Institute of Technology. “They have a lot of social behaviors that sharks do not, which allows them to hunt effectively in groups, communicate among themselves, and teach their young.”
In October 1997, fishing vessels near Southeast Farallon Island observed a young white shark interrupting a pair of orcas that were eating a sea lion. One of the whales rammed and killed the shark, and the duo proceeded to eat its liver. More recently, after orcas passed by a South African beach, five great-white carcasses washed ashore. All were, suspiciously, missing their liver.
A great white’s liver can account for a quarter of its body weight, and is even richer in fats and oils than whale blubber. It’s “one of the densest sources of calories you can find in the ocean,” Jorgensen says. “The orcas know their business, and they know where that organ lies.”
Rather than ripping their prey apart, it seems that orcas can extract livers with surprising finesse, despite lacking arms and hands. No one has observed their technique, but the wounds on otherwise intact carcasses suggest that they bite their victims near their pectoral fins and then squeeze the liver out through the wounds.
“It’s like squeezing toothpaste,” Jorgensen says.
An orca, then, is an apex predator’s apex predator.
No wonder sharks flee from them. But orcas don’t actually have to kill any great whites to drive them away. Their mere presence—and most likely their scent—is enough. Many predators have similar effects. Their sounds and smells create a “landscape of fear”—a simmering dread that changes the behavior and whereabouts of their prey. The presence of tiger sharks forces dugongs into deeper waters, where food is scarcer but cover is thicker. The mere sound of dogs can keep raccoons off a beach, changing the community of animals that lives in the tide pools.
And what about the sharks? “They had to move to find a new food source when the killer whales ruined the neighborhood,” Zanette says. “This could interfere with their ability to successfully migrate, which requires a bulk-up of fat and nutrients.”
“We think of white sharks as these great ocean predators, but their bag of tricks includes knowing when to pack it in,” Jorgensen says. “That play might have contributed to their long-standing success.”
Or, in other words: Run away, doo doo doo doo doo doo, run away, doo doo doo doo doo doo, run away, doo doo doo doo doo doo, run away.