In a recent study on northern resident orcas off the coast of British Columbia, researchers were surprised when Pacific white-sided dolphins unexpectedly joined the scene. While initially considered irrelevant to the study’s focus on orcas’ food-finding behavior, the dolphins revealed a unique collaborative hunting relationship with the orcas. The study, conducted by Dalhousie University, the University of British Columbia (UBC), the Leibniz Institute, and the Hakai Institute, aimed to compare the foraging patterns of northern and southern resident orcas.
Contrary to the common belief that dolphins are fish-stealers, the research discovered that the dolphins were actively assisting the orcas in hunting Chinook salmon. Through deep dives and echolocation communication, the dolphins scouted out the salmon, allowing the orcas to locate and catch their prey. Videos captured orcas following dolphins on dives and eavesdropping on their echolocation signals.
Lead author Sarah Fortune, an assistant professor at Dalhousie University, emphasized that the dolphins were not freeloaders but actively engaged in the hunting process. Despite being smaller than orcas, the dolphins played a crucial role by diving deep to chase salmon, which the orcas then shared with them after the successful hunt.
The study, spanning two years and conducted in the Johnstone Strait and Queen Charlotte Sound, utilized tags attached to the orcas to gather underwater footage. Drone videography provided additional perspectives on the collaborative behavior between orcas and dolphins during hunting expeditions. The research highlighted the intricate partnership and mutual benefits between the two species, shedding light on the complex interactions in nature.
The findings, published in Scientific Reports, underscored the importance of understanding and appreciating the collaborative nature of animal behaviors in the wild. Future research will delve deeper into specific matrilines of northern resident orcas to explore their preferences for foraging with dolphins and assess their physical well-being in connection with this symbiotic relationship.