Dolphins in Australia have learned how to snatch bait from crab traps—and now, researchers say they’ve captured the clever behavior on camera for the first time ever.
The bait-stealing saga may have started two decades ago, when crab fishers off the coast of Bunbury, Western Australia, realized bottlenose dolphins were taking the fish they use as bait from their crab pots and nets. The interactions began occurring in Koombana Bay, a part of the Indian Ocean in far southwestern Australia, about 100 miles south of Perth.
Over time, fishers and local conservationists became concerned about the dolphins’ safety. They not only worried that the fish might be unhealthy, but they were also afraid the marine mammals would become entangled in their gear. And that’s a serious concern: In July 2022, a baby dolphin in Clearwater, Florida, became tangled in the ropes of a crab trap and had to be taken to SeaWorld for medical treatment and rehabilitation.
“It’s a risky behavior,” says Simon Allen, a conservation biologist and co-director of the Shark Bay Dolphin Research Alliance, in a video. “They get some reward out of taking the bait, but then they’re also at risk of entanglement or physical damage from the gear.”
Two years ago, Bunbury conservationist Rodney Peterson got in touch with staff at the Dolphin Discovery Center, a nonprofit conservation and tourism organization, to talk about this problem. Using five cameras, a film team began recording the dolphins, and they were “stunned” by what they saw, the center wrote in a post on Instagram.
“The footage was certainly surprising,” says Axel Grossmann, a volunteer and filmmaker who worked on the project, to the Australian Broadcasting Corporation’s Alexander Govan and Jacqueline Lynch. “We knew something was happening, but we had no clue that the dolphins were acting to such an extent, through so much effort, learning and physical and mental problem-solving [to steal the food].”
In some instances, the dolphins watched the crab fishers hook bait onto their pots. As soon as the humans lowered the pots into the water, the creatures sprang into action and grabbed the fish off the hooks.
The fishers tried other approaches, such as attaching the bait on the bottom of the pot—but the dolphins learned they could use their noses to flip over the whole device and nab the fish.
Next, the fishers tried putting the bait inside a smaller plastic container with a lid. But the dolphins outsmarted them once again: They used their teeth or noses to swiftly pop open the box and spring the fish free.
“There is no doubt that dolphins are intelligent,” the center wrote on Instagram. “Being brilliant observers, fast learners and innovators helps the most bold and sophisticated animals to succeed.”
Eventually, the team devised a dolphin-proof solution: a mesh bait pouch with a metal hook that “kept the bait closed in tight,” Grossmann tells Live Science’s Lydia Smith.
“The dolphins learned that it wasn’t accessible, so they swam off,” he adds. “It means we get healthier dolphins and happier crab fishermen.”
The film project raises additional questions about the behavior, such as whether it’s widespread or isolated to just a few individuals. Researchers also aren’t sure why the dolphins are going to such great lengths to steal the bait, which is not a substantial meal. But they suspect it’s some mix of hunger, curiosity and fun, reports Live Science.