Footage captured by enthusiastic ecotourists reveals an extraordinary predatory act by orcas: the killing of a colossal whale shark. This is just one of the many feats achieved by these killer whales. Researchers suggest that a pod of orcas in the Gulf of California is specializing in hunting sharks and their kin, based on four videos of orca hunting sprees, the oldest from 2018 and the most recent from 2024. Marine biologist Francesca Pancaldi of the marine science center in La Paz, affiliated with Mexico’s Instituto Politécnico Nacional, notes that other targets include popular ecotourist attractions like mobula rays. Pancaldi and her team present their findings on orca specialization on November 29 in Frontiers in Marine Science.
Orcas are renowned as top-tier and highly adaptable predators in the world’s oceans. Orcinus orca pods have been observed taking down adult great blue whales off the coast of Western Australia and harassing boaters off the Iberian coast. They prey on sea turtles, cephalopods, and seabirds. Some orcas even use a “karate chop” technique on thresher sharks, while others beach themselves to capture vulnerable pinnipeds.
The feeding habits of orcas in the eastern tropical Pacific Ocean are still largely unexplored, according to coauthor Erick Higuera Rivas, a marine biologist at Conexiones Terramar in La Paz. The whale sharks targeted by orcas are the largest fish in the world, capable of growing up to 18 meters in length, possibly more. Despite their massive size, whale sharks are filter feeders and lack biting teeth, feeding on the sparse background-soup of ocean life.
Orcas’ physiology poses challenges in catching whale sharks. “They have lungs,” says Pancaldi, whereas whale sharks, with gills, can dive to depths of 2,000 meters and stay submerged indefinitely. To hunt sharks, orcas need to prevent them from diving, a task that requires a coordinated effort by the pod. Orcas chase and harass the sharks, with even young and small orcas participating by snapping or blocking escape routes. Flipping the shark over or startling it into tonic immobility is a significant success. Biting off the pelvic fins and claspers from the shark’s lower body leads to its demise by bleeding out. The orcas then feast on the shark’s liver, which is large and rich in fat, discarding the rest.
All four sharks in the videos were young and small, measuring only five to six meters in length. Three of the four videos feature the same orca, a distinctive male nicknamed Moctezuma by the researchers. However, it is the grandmothers, particularly the matriarch of the pod, who pass down cultural knowledge, including techniques for obtaining the prized shark livers.
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