Hello and Thanks for All the Fish

Dolphins are savvy, opportunistic hunters. Adaptive and social, it turns out that part of their hunting strategy involves helping others to hunt. Dolphins collaborate with fishermen to herd mullet into nets around the world, from Brazil to Australia. We have evidence this partnership goes way back: Art on rocks painted by Aboriginal people shows cooperative hunts with dolphins.

The dolphins will herd schools of fish into shallow water and use jumps and tail slaps to let people know it's time to throw the nets.

The fishers communicate with the dolphins to let them know they are in position with specific cues, like tapping out a rhythm on the side of a boat. Both the dolphins and people benefit from this relationship. Humans get more fish with less work, and dolphins chow down on stragglers, who are less able to avoid being caught when outside the school.

The mutual advantage has been reinforced culturally in dolphins via social learning within pods and in humans through local traditions. This co-hunting is a rare case of a cross-species system of cooperation. But it's also a fragile social relationship that can break down if either the local human or dolphin population changes.

Scientists have known about the dolphin and human fishing partnership for decades. What's new is a study published in Scientific Reports in December of 2025 that reveals another cross-species hunting partnership. White-sided dolphins in the Pacific and killer whales team up to hunt Chinook salmon.

Dr. Sarah Fortune, a marine ecologist at Dalhousie University in Nova Scotia, led the research team in the waters off Vancouver Island, British Columbia. The scientists became interested after seeing dolphins and killer whales in close proximity on several occasions. To figure out what was happening, they attached high-tech sensor tags to killer whales that recorded underwater video, sound, and movement data and drones to film the whales and dolphins from above.

What they found is that the dolphins were acting as scouts to help locate fish while the killer whales do the actual catching and killing. The adult Chinook salmon are too big for dolphins to swallow whole, so the dolphins settle for eating the scraps left behind after the killer whales tear the fish apart. The researchers ruled out the idea that the dolphins were simply stealing from the whales. Like in the human/dolphin coordination, both species were genuinely hunting together. At no point did either side get aggressive or competitive about the hunt.

Scientists called the behavior "opportunistic association," which is just a sciency way of saying that dolphins are good at cooperating with others.

Read the full stories
Sharks and Co, July 10, 2025
Scientific Reports, December 11, 2025

Hot Take: Douglas Adams gave us the skinny on dolphins back in 1984 in So Long and Thanks for All the Fish. Humans keep underestimating dolphins because we interpret their behavior as play instead of deliberate strategy and communication.