Sunita SomvanshiDr Alexis Levengood was screaming. Not in fear, but in recognition. The marine mammal researcher from the University of the Sunshine Coast was watching footage of two Indo-Pacific bottlenose dolphins in Queensland’s Hervey Bay, and she knew exactly what she was seeing: shelling, a sophisticated fishing technique that had only ever been documented on the opposite side of Australia.
“I started screaming because I know what shelling looks like,” Levengood said of the moment she realised the significance of the video recorded in Butchulla Country’s Great Sandy Marine Park. The Conversation published the peer-reviewed study in Marine Mammal Science, with Levengood as lead author. The University of the Sunshine Coast covered the discovery on its newsroom site.
Shelling is a hunting strategy where a dolphin chases a fish into a large, empty sea snail shell, then carries the shell to the water’s surface and shakes it. The fish drains into the dolphin’s mouth. It is, by any measure, a deliberate, complex use of a tool—the kind of behaviour scientists associate more with primates than with marine mammals.
Levengood’s team documented two adult female dolphins performing shelling in July 2025 and October 2025. The sightings might have remained a local curiosity, but they matter enormously to marine science: they mark the first published record of shelling on Australia’s east coast. Before this, the only known published evidence came from Shark Bay, Western Australia—over 6,000 kilometres away.
The significance deepens further. During the October sighting, the second female’s calf picked up the shell within minutes of its mother dropping it. The calf held the shell in the same way as its mother, apparently with a lizardfish dangling from it. This behaviour suggests maternal social transmission: the calf learning by watching, then mimicking its mother’s actions. The observation calls into question the prevailing scientific belief that dolphins acquire tool use by learning from their peers. The study notes the calf “picked up the shell within minutes after the mother dropped it” — the first potential evidence of maternal social transmission ever captured on film.
“Our footage provides the first potential evidence of maternal social transmission—a process by which offspring learn behaviour by observing the actions of its mother,” Levengood said. “It calls into question the belief that dolphins learn this tool use from their peers.”
The independent development of the same technique by dolphins on opposite sides of Australia suggests possible convergent cultural evolution. “Our observations in Queensland show that dolphins on opposite sides of Australia have learned to use tools in the exact same way, independent of one another,” Levengood noted.
That two distant populations developed identical techniques without contact suggests the behaviour emerged from problem-solving within each group—a marker of genuine intelligence and innovation. Shelling is not instinctive. It is learned, refined, and in some cases, taught.
Local tour operators from Blue Dolphin Marine Tours had photographed shelling behaviour as far back as 2013 and 2019, but the sightings went unrecorded in academic literature. The region had simply received limited research attention until now.
Shelling places dolphins within a broader tradition of animal tool use. In Shark Bay, dolphins wear bowl-shaped basket sponges on their rostrums—their beaks—as protective armour when foraging through rubble-littered sea floors. Jane Goodall’s 1960s documentation of chimpanzees fishing for termites stands as one of the landmark early records of documented non-human tool use. New Caledonia crows fashion twig hooks to extract insects from crevices. Octopuses carry coconut shells for portable shelter. Other recent research has shown that wild fish can recognize individual human divers by their gear, further expanding our understanding of animal cognition in the marine environment.
Tool use is a marker of cognitive complexity in animal behaviour studies. The dolphins of Hervey Bay represent an example of this in action, expanding what researchers know about how animals learn, teach, and survive.
