A gang of orcas uses an Ingenious techniques to hunt whale sharks in Mexico | Science

Moctezuma — the last Aztec emperor, before the Spanish invasion — is the name chosen by researchers to baptize a male orca. In the Gulf of California, along the northwestern coast of Mexico, he leads a pod of fellow orcas in sophisticated hunts against whale sharks.“He’s at least 30-feet-long and we estimate that he’s around 50-years-old, because he was already photo-identified in 1988, on Angel de la Guarda Island. He’s healthy and strong,” says Erick Higuera. He’s a marine biologist who has specialized in observing and photographing marine life for almost 30 years.When Moctezuma hunts, he moves stealthily through the sea. He likes to attack the pelvic area of his prey, so as to take advantage of the liver, which is large enough to provide a whole meal for all members of the clan. Higuera is the co-author of a recent study published in the journal Frontiers in Marine Science. The work describes, in detail, the hunting behavior of the Moctezuma-led gang of killer whales against the largest fish in the sea.The scientists — led by Francesca Pancaldi, a researcher at the Interdisciplinary Center for Marine Sciences in La Paz, in the Mexican state of Baja California Sur — collected images captured between 2018 and 2024 south of the gulf, thanks to material provided by tourists and fishermen in the area. The desert land area contrasts with the biodiversity that exists underwater: almost 40 types of cetaceans (marine mammals) and 100 species of sharks that move between mangroves, rocky reefs and seamounts. “These attacks had already been reported in several areas of the Mexican Pacific. Let’s say that this is the first time it’s been described in detail,” Pancaldi explains.Each orca has unique characteristics, like fingerprints in humans. The orcas in this particular pod were identified by analyzing photographs of their dorsal fins, natural markings — the patterns of white spots on their backs — or eye patches, which vary between each specimen, as well as distinctive aspects, such as scars and wounds.Of the four hunting events recorded, scientists realized that Moctezuma participated in all of them. “I realized that they were the same orcas all the time, there was a strategy and a directed objective,” Higuera notes.In the hunt, all members of the pod — led by a matriarch — participate by striking the prey, until it flips upside down. According to Pancaldi, whale sharks have small teeth and are relatively slow. The only way these animals have to defend themselves is to hit their attackers with their tails and dive, since they can reach depths of 6,500 feet. For this reason, orcas try to keep them at the ocean surface.Jessica Rodriguez — head of education and communications at the whale watching agency Davey’s Locker, in Newport Beach, in the United States — indicates that, in general, the orcas hunt together like wolves on land, coordinating specific tactics. “If you’re observing orcas in Mexico — which feed on mammals such as whales, dolphins and sea lions — they’re going to have different feeding strategies. The oldest female transmits this generational knowledge,” says Rodriguez, who wasn’t part of the new study.The whale shark is brought to the surface and an orca bites near its pelvic area.Kelsey WilliamsonRicardo Aguilar — the European research director for the NGO Oceana, who didn’t participate in the newly-published research — agrees with this. He explains that almost all groups of orcas are different and have fairly rapid learning processes. “This means that the entire group ends up learning this new behavior and integrating it,” the expert says.Oceanic dolphins — the group of marine mammals to which orcas belong — have one of the largest brains in relation to their body size, which allows them to develop extraordinary skills. They’re sociable animals and have a good memory, factors that possibly guarantee the success of capturing prey in “the aquarium of the world.” This is how oceanographer Jacques Cousteau defined the expanse of the Pacific Ocean occupied by the Gulf of California.Although this gulf is one of the most diverse habitats on the planet, marine animals are vulnerable here, because they’re exposed to collisions with vessels. This problem has only gotten worse, due to high-speed maritime traffic. The boats, Francesca Pancaldi explains, sometimes go “very fast” in certain areas.Naming the orcas was a strategy that researchers devised to generate empathy from the community, fishermen and even tourists. “People liked the Aztec names. The collaboration has been very successful,” Erick Higuera affirms. Fabiola Guerrero de la Rosa — a marine biologist at the University of Baja California Sur — points out that the more information people get, the more careful they’ll be. “It’s not the only place where orcas have been named. In British Columbia [Canada], we know the life and work of each one of them, from the mother to the grandmother. Giving them names helps identify them and give them a backstory,” she says.There’s another male orca, with “several battles” reflected on its skin. Scientists have named him Cuitláhuac, after Moctezuma’s brother, who was the penultimate huey tlatoani (the great orator, or ruler, in the Nahuatl language) of the Aztec dynasty. “After seeing them in the sea for so long, your eye gets used to them. It’s like when a bird visits your backyard constantly, you become familiar with it,” Higuera reflects.Translated by Avik Jain Chatlani.