Researchers in British Columbia used drones and orca-mounted cameras to document 25 occasions when northern resident orcas and Pacific white-sided dolphins appeared to hunt together, a finding reported in Scientific Reports. Footage shows the species coordinating at depths of about 197 feet while both echolocated, suggesting possible cross-species "eavesdropping." Scientists say the behavior could reflect mutual foraging benefits or a response to dwindling Chinook salmon stocks and call for more research to assess prevalence and conservation implications.
Orcas and Dolphins Filmed Hunting Together — Possible First Recorded Collaboration
A pod of northern resident killer whales travels together. The same population of orcas was recently seen hunting with Pacific white-sided dolphins. Scientists think the partnership is the first example of orcas teaming up with another species to hunt.Dalhousie University, S. Fortune
Scientists using drones and whale-mounted cameras have for the first time documented what appears to be coordinated hunting between northern resident killer whales (orcas) and Pacific white-sided dolphins off British Columbia. The observations — described in a new paper in Scientific Reports — include 25 separate encounters in which orcas followed dolphins as the dolphins dove for prey.
Choppy seas and poor visibility had long prevented researchers from understanding surface interactions: orcas would surface to breathe while dolphins darted around their heads, leaving observers to guess what was happening underwater. By combining aerial footage with forward-facing video from suction-cup tags placed on individual orcas, the research team gained a direct view of below-surface behavior.
What the Footage Shows
Video and acoustic recordings captured the two species moving together as dolphins chased salmon and orcas oriented toward those dolphins. In one filmed instance, dolphins circled the head of an orca after it had caught a Chinook salmon, snapping up fragments of fish and scales that escaped the whale's mouth. The animals were recorded working together at depths of roughly 197 feet (about 60 meters), where light is dim and the silhouettes of several dolphins could still be seen near the orca's head.
"There was some organization to the chaos," says Sarah Fortune, an author of the study and an assistant professor of oceanography at Dalhousie University.
Echolocation and Possible Cross-Species Eavesdropping
Underwater acoustics show both species clicking and echolocating, sometimes in alternating patterns. The researchers suggest this may indicate that the animals are "eavesdropping" on each other's sonar to locate prey — a potential example of interspecific information sharing. Confirming true cross-species communication will require additional study, but experts call the idea intriguing.
Why It Matters
Northern resident orcas in the northeastern Pacific specialize in eating Chinook salmon, a species now threatened by warming rivers, reduced stream flows, habitat loss, and overfishing. Pacific white-sided dolphins typically feed on smaller schooling fish such as herring and anchovy. Researchers hypothesize that dolphins may help orcas locate salmon, while dolphins benefit from scavenging scraps too large for them to consume whole.
Scientists caution that this apparent cooperation may be an adaptive response to changing prey availability. "If these collaborations are new, what is happening in the environment that’s necessitating this novel behavior?" asks Ari Friedlaender, a coauthor quoted in the study. If orcas and dolphins forage together more often when Chinook are scarce, the behavior could signal broader ecosystem stress and strengthen calls for stricter salmon conservation.
Next Steps
The authors plan further work to determine how common these encounters are, whether orcas capture more salmon when accompanied by dolphins, and whether such pairings affect orca condition, health, and reproduction. Researchers also emphasize that advances in lightweight cameras and drones are allowing scientists to see underwater behaviors previously hidden from view.
Bottom line: New technology has revealed a potentially cooperative hunting strategy between two marine predators. Whether this represents long-standing behavior or a response to dwindling salmon stocks remains an open and important question for conservation.
