Indo-Pacific bottlenose dolphins in Queensland’s Great Sandy Marine Park have been observed using seashells as tools to trap and drain fish, a behavior previously documented only in Western Australia. Researchers suggest this complex foraging tactic, known as “shelling,” likely emerged independently in these two populations separated by 4,000 kilometres.
Documenting Shelling in the Great Sandy Marine Park
While shelling has been studied for years in Shark Bay, Western Australia, the recent confirmation of the behavior on the opposite side of the continent provides a new window into dolphin innovation. Research led by Alexis Levengood and colleagues, recently published in the journal Marine Mammal Science, details observations made in the Great Sandy Marine Park since 2022. The study confirms that this specialized foraging technique is not unique to the western coast.
The research team documented two specific encounters in Hervey Bay during 2025. On July 6, a dolphin identified as Stevie Nicks was observed positioning a large baler shell—Melo amphora—at the water’s surface to trap prey. Later that year, on October 1, the researchers captured drone footage of a mother dolphin named Maserati repeatedly surfacing with a shell. Her calf, Bentley, was seen performing the same maneuver just minutes later.
These findings align with anecdotal reports from local tour operators, who provided photographs of dolphins using shells in the same region dating back to 2013 and 2019. These older images suggest that while the practice went unnoticed by the scientific community for over a decade, it has been part of the local population’s repertoire for quite some time.
The Mechanics of a Specialized Foraging Tool
Shelling is a sophisticated foraging strategy that requires more than simple object manipulation. To successfully capture a meal, a dolphin must locate a dead gastropod shell, identify a fish hiding inside, and carefully maneuver the heavy shell to the surface. By lifting the shell out of the water, the dolphin drains the liquid, forcing the trapped fish into its mouth.
Much like other tool-using species, such as chimpanzees using sticks to extract termites or crows fashioning twigs into hooks, dolphins must adapt to their specific surroundings. In this case, the empty shells act as a trap, turning a fish’s natural refuge into a tool for the predator.
Independent Innovation and Maternal Learning
The geographic distance between Shark Bay and Hervey Bay—roughly 4,000 kilometres—suggests that the two dolphin populations likely developed the technique without any interaction. There is no evidence of a social link that would allow the behavior to be passed directly between these distant groups.
Within the Queensland population, however, the transmission of the skill appears to be social. The observation of a calf mimicking its mother’s technique within minutes of her dropping the shell provides potential evidence of maternal learning. Researchers emphasize that because calves spend significant time with their mothers, they have ample opportunity to observe and acquire these complex foraging tricks.
The study highlights how quickly such behaviors can spread once an individual discovers a successful method. While many questions remain regarding why some dolphins choose to shell—whether it is a response to food competition or simply a more efficient way to hunt—the discovery confirms that these marine mammals possess a capacity for innovation that continues to challenge human assumptions about animal intelligence.
