Hard to resist an underbelly that white and that soft, right? Photo: Kelsey Williamson//Frontiers in Marine Science
Orcas are endlessly fascinating creatures. Their antics — from sinking ships to sucking out the livers of great white sharks — have been the focus of the internet’s interest more than usual in recent years, and now, they’re up to something else: hunting whale sharks.
Mother Nature can be pretty gruesome, and for a society that doesn’t necessarily equate eating meat with animal death, it can be hard to see the stark reality. Whale sharks are the world’s biggest fish, growing to almost 60 feet long. They’re docile animals, feeding on small fish, crustaceans, and plankton. Despite their size and the word shark in their names, though, they pose no threat to humans.
Orcas, while also no threat to humans (in the wild, anyway), are apex predators. They’re smart, like very smart, and they use those smarts to engage in cooperative hunting. Because of that, they feed on a wide variety of animals, like seals, sea turtles, cephalopods, sharks and other fish. And now, whale sharks.
“Due to their enhanced cognitive abilities, they are frequent predators of other ocean giants, including large sharks,” researchers wrote in a recently-published paper in Frontiers of Marine Science. “Observations of these predator-prey interactions are rare globally; however, records appear to be increasing in recent years, possibly due to increased access to surveillance.”
The new behavior was studied and a written up for the study, and researchers believe there’s a group of orcas that live mostly in the southern Gulf of California that have begun targeting sharks and rays. Over the last six years, researchers have documented four separate whale shark/orca predation events. Some of the evidence comes from so-called “citizen scientists,” who shared video and images of the behavior. This allows the researchers to not only study the behavior in greater detail, but even to identify the orcas involved in it.
One orca in particular seems to be a bit of a ring leader. Moctezuma, a male killer whale, was there for the majority of the whale shark hunts.
“According to the events,” the study’s authors wrote, “killer whales displayed a cooperative and coordinate hunting behavior which included repeatedly hitting the whale shark at high speed to stun and immobilize it, manipulate and positioning the shark ventral side up and biting the shark in the exposed ventral region, to exsanguinate the shark through the cloaca and allow access to the organs for consumption.”
According to the study, the orcas direct their attacks at the pelvic area of the whale sharks. This bleeds the whale shark out quickly and gives easy access to the liver, which orcas appear to have a bit of a taste for.
The orcas use cooperative hunting techniques to kill their prey. Photo: Kelsey Williamson//Frontiers in Marine Science
It’s theorized that the orcas target the whale sharks’ underbellies because they are, like most underbellies, soft. The orcas mostly target juvenile whale sharks, which could offer more proof to back that theory up. Juveniles have even softer underbellies, so getting at the tasty innards is that much simpler.
“When hunting, all pod members work together, hitting the whale shark to turn it upside down. In that position the sharks enter a state of tonic immobility and can no longer move voluntarily or escape by going deeper,” Higuera Rivas explained. “By keeping it under control, the orcas then have greater ease and speed in approaching the pelvic area of the shark and are able to extract organs of nutritional importance for them.”
Getting chewed open by a gang of orcas would be an undoubtedly bad way to go, but as mentioned, Mother Nature can be gruesome. It does shine even more light on the level of intelligence orcas have.
“It is very impressive how orcas work together strategically and intelligently to access only a very specific area of the prey,” concluded Rivas. “It highlights what great predators they are.”
