A recent study on northern resident orcas off the coast of British Columbia took an unexpected turn when Pacific white-sided dolphins made an appearance. Initially seen as an interruption to the study’s focus on orca feeding habits, the dolphins ended up revealing a unique foraging relationship with the orcas. Researchers from Dalhousie University, the University of British Columbia (UBC), the Leibniz Institute, and the Hakai Institute aimed to investigate how northern resident orcas locate food, especially in comparison to the declining southern resident population.
Contrary to the belief that dolphins steal fish from orcas, new research published in Scientific Reports revealed that the dolphins were actually assisting the orcas in hunting Chinook salmon. The study’s lead author, Sarah Fortune, emphasized that the dolphins actively participated in deep dives to track and chase salmon, indicating a collaborative effort with the orcas.
Videos captured by the researchers showed orcas following dolphins on dives, suggesting a coordinated hunting strategy. The orcas were observed listening to the dolphins’ echolocation signals to locate salmon. Once the dolphins detected a large Chinook salmon, the orcas moved in to secure the prey, eventually sharing it with other orcas. The dolphins then fed on the leftover scraps, highlighting a mutually beneficial relationship.
The two-year study, conducted in the summer of 2019 and 2020 in various locations, involved underwater footage collected using tags attached to the orcas. The tags allowed researchers to track the orcas’ behavior and interactions with the dolphins. Drone videography provided additional perspectives on the unique collaboration between the two species.
The study recorded numerous instances of dolphins assisting orcas in foraging, with the interactions observed only in 2020. Janie Wray, CEO of B.C. Whales, commended the research for shedding light on the intricate connections and cooperation among animals in the wild. The findings underscore the importance of understanding and appreciating the collaborative dynamics between different species in natural ecosystems.