A Pod of Orcas Learned to Target and Feast on Whale Sharks, the Largest Fish in the Sea

In the southern Gulf of California, a pod of killer whales surfaces in the glassy morning water. It’s hunting time. But for this group of orcas—unlike other orca groups in the Pacific or the Atlantic—it seems no prey is too large. Not even a whale shark, the biggest fish species on Earth.

In a new study published in Frontiers in Marine Science on November 28, scientists shared videos and photos showcasing the animals’ behavior. The footage was taken in May by photographer Kelsey Williamson and shark ecologist Kathryn Ayres during an ocean safari tour near La Paz, Mexico.

“It was raining whale shark,” Ayres tells National Geographic’s Brianna Randall, after seeing the action up close. First, the orcas rammed into the whale shark to immobilize it, then they flipped it upside down. They tore off its pelvic fins and ate the prey’s organs, including the liver, which is known for its fatty content.

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A post shared by Kelsey Williamson (@kelseywilliamson)

José Armando Osuna, a local living in La Ventana, Baja California Sur, in Mexico, is familiar with the resident groups of orcas living in the Gulf of California. He’s also been witness to their whale shark-eating behavior while leading whale watching and kitesurfing tours in the gulf. When he saw the orcas feasting, he felt like he wanted to help the shark. “The whale shark is so noble, so gentle, so calm,” he tells Smithsonian magazine. Seeing that moment caused a flurry of emotions for the captain, who was not involved with the new research.

Sightings like his can help paint a clearer picture of orcas’ hunting behaviors. And thanks to the photos and videos shared in the study, scientists have deciphered precisely how orcas are able to take down these whale sharks.

Although there had been reports of orcas preying on whale sharks in the past, this paper is the first to describe the repeated behavior by a specific pod. The orca group has repeated the behavior at least four times, and the same 50-year-old male, named Moctezuma after an Aztec emperor, was present for three of the documented hunts.

The events spanned the course of six years, from 2018 to 2024, the study says. The orcas have worked collectively as a group to take down these filter-feeders. Lead author Francesca Pancaldi, a marine biologist at the National Polytechnic Institute in Mexico, says the documented attacks have been against juvenile whale sharks, as they are “definitely the most vulnerable,” she tells the New York Times’ Jason Bittel.

The orcas target the whale sharks’ ventral sides, thought to be the least protected part of the body. “It is very impressive how orcas work together strategically and intelligently to access only a very specific area of the prey,” said Erick Higuera Rivas, a marine biologist at Conexiones Terramar, in a statement.

Whale sharks tend to aggregate in the Gulf of California from October to May, in relation to plankton blooms. These provide the filter-feeding sharks with their main food source, turning the waters into a rich feeding ground for juveniles during those months. Whale sharks are often called “gentle giants,” as they’re known for their tranquil filter-feeding, despite their massive size. Adults can reach 60 feet long, sometimes more, but juveniles tend to be 20 to 26 feet in length.

While the recorded events have only involved juvenile whale sharks, Pancaldi tells National Geographic that “orcas are smart enough to put down a big whale shark, as well.”

Orcas are known for taking down larger animals or even other predators. In the past, they’ve hunted blue whales and great white sharks. They can easily adapt to the available prey depending on the ocean they’re in. In the case of the Gulf of California, that means they’ll eat the largest fish in the sea.

“I’ve never heard of whale sharks being targeted by orcas anywhere else in the world,” says Simon Pierce, a whale shark conservationist not involved in the study, to National Geographic.

The orcas hunting as a group is a targeted strategy. Pierce tells the outlet, “I can’t imagine a whale shark has much of a chance if a pod of killer whales zeros in on one.”

For now, the pod of orcas continues its dominion over the southern Gulf of California. Those fortunate enough to catch a glimpse of these apex predators may witness their next hunt and behold this strategy in action.

Alexa Robles-Gil | | READ MORE

Alexa Robles-Gil is a bilingual science journalist based in New York City. Her work has appeared in the Guardian, Undark, Inside Climate News and more.