In the cold waters of the northeast Pacific off British Columbia, salmon hunting can turn into a team effort. The protagonists of this unexpected alliance are northern resident
The research is based on observations made in the summer of 2020 near Vancouver Island. Scientists monitored nine orcas through a combination of tools: movement tracking, underwater footage, acoustic recordings and aerial images taken with drones. Painstaking work that has allowed them to reconstruct hunting dynamics never before described in such detail.
On at least 25 occasions, killer whales deliberately changed their course after encountering groups of dolphins, following them whilst diving for prey. A behaviour that, according to the study’s authors, points to a form of true cooperative hunting: dolphins, thanks to particularly efficient echolocation, would locate salmon, whilst orcas–physically better equipped–would do the catching.
Killer whales, once caught, tend to share their booty within the pod and, in some cases, even in the presence of dolphins. Researchers have documented eight episodes of salmon capture and sharing amongst orcas, four of them with dolphins in close proximity.
The study also opens up for broader interpretations. The collaboration could offer mutual benefits: killer whales benefit from the sensory capabilities of dolphins, while the latter may find killer whales an indirect form of protection from other predators or competing groups. At present, however, these are hypotheses that will require new observations to confirm.
One thing is certain: the image of the great lone predator falters once again. At sea, as on land, intelligence counts as much as strength. And sometimes, to eat, it pays to team up.
