Dolphins on opposite sides of Australia independently developed the same shell-based fishing technique, a study reveals, with mothers teaching their young to use seashells to trap fish—a behavior observed in 2025 and possibly dating back to 2013.
Independent Innovation Across Oceans
Four thousand kilometers separate Shark Bay on Australia’s west coast from Hervey Bay on the east, yet bottlenose dolphins in both regions have independently mastered the same unusual foraging method: using large empty seashells to trap fish. Researchers documented this behavior in a 2025 study published in Marine Mammal Science, marking the first recorded instances of shelling in Queensland’s Great Sandy Marine Park. The study suggests the tactic emerged separately in each population, though the exact moment of invention remains unknown.
The Role of Maternal Teaching
The study also highlights the critical role of maternal instruction. In Hervey Bay, a mother dolphin’s calf was seen mimicking her shell-lifting technique within minutes of her dropping the object. This footage provides the first potential evidence of maternal social transmission,
the researchers noted. Similar patterns have been observed in other dolphin populations, such as those using sponges to forage, where calves learn by watching their mothers. Calves depend on their mothers for so long, they have plenty of time to learn from them,
the study explained.
Technical Precision and Ecological Context
Shelling involves more than simply carrying a shell. A dolphin must locate a suitable shell, position it to trap a fish, and lift it to drain the prey. The process demands precise timing and coordination. In one encounter, a dolphin named Stevie Nicks was observed lifting a shell across three surfacings, though no fish was confirmed to have been captured. Earlier sightings in 2013 and 2019—though less detailed—suggest the behavior may have been present in Queensland for over a decade.
The study’s authors note that the geographic separation between Shark Bay and Hervey Bay makes direct cultural transmission unlikely. There is no plausible chain of ordinary dolphin associations connecting the two study sites,
they wrote. However, similar ecological conditions—such as the availability of large shells and small fish that seek shelter in them—may have driven the parallel innovation. Shelling is a compact example: buoyancy helps move a large shell, while gravity becomes useful only when the dolphin lifts it clear of the surface,
the researchers observed.
Unanswered Questions and Future Research
The study in Marine Mammal Science and the findings on maternal transmission provide a foundation for further exploration into dolphin cognition and cultural practices.
