Tales of human-dolphin interactions have been told for millennia. Many are fantastical—featuring dolphins that hijack pirate ships or give children rides to school. But for artisanal fishers in Brazil, working with dolphins isn’t make-believe: It’s a way of life.
In Laguna, Brazil, local newspapers chronicle the cooperation between humans and dolphins over the last 150 years. Native, wild bottlenose dolphins help fishers catch mullet fish. Scientists have studied this unusual teamwork, called “synchrony,” since the 1980s.
Biologists Mauricio Cantor, Damien Farine, and Fábio Daura-Jorge wanted to know more about Laguna’s tag-team fishing. Their research, published in the journal Proceedings of the National Academy of Sciences, details the phenomenon.
The researchers used sonar and underwater microphones to track the positions of dolphins and fish. “The water is really murky here, so the people can’t see the schools of fish. But the dolphins use sounds to find them, by emitting small clicks,” says Cantor. He likens the clicks to how bats use echolocation.
Drones recorded interactions from the sky. GPS devices attached to fishers’ wrists recorded when the fishers cast their nets.
“We combined about seven different types of data to record interactions simultaneously,” Cantor says.
Here’s what happens: Dolphins herd fish toward shore. Fishers stand waist-deep in dark water, nets at the ready. Suddenly, a tail slap or arched back from a dolphin cues the fishers. They throw their nets. The better the fishers time their net-casting to the dolphins’ signals, the more likely they are to snare a large catch.
“This study clearly shows that both dolphins and humans are paying attention to each other’s behavior, and that dolphins provide a cue to when the nets should be cast,” says biologist Stephanie King.
The falling nets startle the mullet. The fish break into smaller schools that are easier for dolphins to hunt. The fishers catch some; the dolphins catch some!
“The dolphins may also take one or two fish from the net. Sometimes fishers can feel dolphin tugging a little,” says Cantor.
Humorously, Laguna residents categorize dolphins as “good,” “bad,” or “lazy”—based on their cooperation with humans, says Cantor. The people get most excited when they see a “good” dolphin approaching shore.
Study authors believe the so-called “Laguna alliance” is one of the last remaining cases of human-wildlife cooperation. They worry the collaboration may be in danger as traditional fishing gives way to more modern methods.
“This human-wildlife interaction, which is mutually beneficial for both parties,” Cantor says, “is inspiring.”
Why? A proper view of creation leads to kindness toward God’s creatures. Since God made all things and by Him they exist, He must be pleased when His creatures work together.