Orcas and sharks: a silent battle unfolds in the Gulf of California. For several years, scientists have observed orcas attacking sharks, particularly bull sharks and blacktip sharks. This rare and alarming spectacle could disrupt the local ecosystem.
Orcas after a successful bull shark hunt.
a) Adult female orcas involved in predation on a bull shark; arrows indicating a shark in the mouths of the adult female orcas.
b) Two adult female orcas sharing a bull shark (C. leucas) near the surface.
c) Image of "Niich" at San José del Cabo, Los Cabos, Mexico in May 2018, during predation on pelagic rays.
d) Image of "Niich" during predation on a bull shark (Event III).
e) "Waay" at a blacktip shark aggregation site (Event I).
f) "Waay" with a bull shark carcass in the mouth (Event III).
Photo credits: Jesús Erick Higuera-Rivas (c, e) Luis Mario Castro Arvizu (a, b, d, f). Three orcas, nicknamed Quetzalli, Niich, and Waay, are at the center of these documented attacks between 2022 and 2023 in the Cabo Pulmo National Park, a marine protected area. Scientists are questioning the ecological impact of these hunts: will the sharks eventually flee the region?
On January 9, 2022, a drone filmed six orcas patrolling an area frequented by numerous blacktip sharks. Two adult females separated from the group to chase a shark, but it managed to escape into deeper waters.
Two weeks later, on January 21, 2022, a local diving guide observed a coordinated attack on a bull shark. The orcas employed a sophisticated hunting technique called "lob-tailing," striking the shark with their tails to disorient it. Despite their persistence, the shark managed to take refuge near a boat.
On December 6, 2023, a similar attack resulted in the shark's death. Underwater videos captured the orcas with their prey between their jaws. This predation behavior on sharks, although known for 50 years, remains rarely observed.
The study's author, Jesús Erick Higuera-Rivas, explains that orcas hunt sharks for their liver and entrails, rich in nutrients. According to him, the increase in observations could be attributed to modern technologies like drones and underwater cameras rather than a real rise in predation.
The ecological impact of these hunts remains uncertain. In South Africa, orcas hunting great white sharks caused a massive flight of these predators. However, it is difficult to predict a similar scenario in the Gulf of California. Experts emphasize that top predators like sharks play a crucial role in maintaining the balance of ecosystems.