ISTANBUL

Orcas and dolphins have for the first time been seen jointly hunting salmon off British Columbia, Canada, according to a new study suggesting a cooperative relationship between the predators.

The study, published on Thursday in the journal Scientific Reports, stated that encounters between northern resident orcas and Pacific white-sided dolphins are intentional rather than random meetings during foraging.

Researchers said the highly specialized salmon-hunting orcas were unexpectedly seen following dolphins as if they were leading.

Dolphins are often seen near northern resident orcas, a salmon-dependent ecotype, even though dolphins cannot catch the much larger Chinook salmon and usually feed on herring instead.

Study footage shows dolphins acting almost like scouts, rapidly pursuing large salmon with orcas close behind. Once the orcas catch and share the fish, dolphins move in to feed on the leftovers, a presence that the normally protective orcas tolerate.

Researchers explored several explanations for the dolphins’ close presence, including seeking protection from predatory Bigg’s orcas, benefiting from reduced drag while bow riding, or stealing leftover food from the resident orcas.

However, the lack of aggression suggested the dolphins were not simply opportunistic feeders. Instead, the authors concluded the two species may be actively cooperating, with orcas appearing to follow the dolphins’ lead.