Researchers have captured the first published record of bottlenose dolphins using large sea snail shells to catch fish off the Queensland coast in October 2025. The rare foraging behaviour, known as shelling, was observed in the Great Sandy Marine Park, challenging previous assumptions about how marine mammals transmit tool use across generations.
Tracking Shelling Behaviour in Queensland Waters
Scientists working with the University of the Sunshine Coast documented bottlenose dolphins engaging in a specialized hunting tactic across multiple sightings in the Great Sandy Marine Park off Hervey Bay. Researchers recorded the animals between July and October 2025, marking the first time the phenomenon has been formally documented on Australia’s east coast.
The practice, commonly termed shelling
, requires a specific sequence of physical coordination. A dolphin chases a target fish into a large, empty sea snail shell, lifts the heavy object out of the water column, brings it near the surface, and shakes it upside down to drain the trapped prey directly into its mouth.
“We were on a research boat off Hervey Bay when we spotted a dolphin raising something large out of the water. I started screaming because I know what shelling looks like.”
Alexis Levengood, co-author of the study published in Marine Mammal Science
While commercial tour operators in Hervey Bay reported observing similar behaviour during boat trips as early as 2013 and 2019, those encounters lacked formal scientific study. Until this recent documentation, the only established evidence of shelling came from a distinct dolphin population more than 3,000 kilometres away in Shark Bay, Western Australia.
Challenging Long-Held Theories of Social Transmission
The October 2025 fieldwork yielded drone footage and photographs that offer potential evidence of maternal social transmission. Researchers observed an adult female dolphin and her calf shelling together, providing a window into how offspring acquire complex skills.
Historically, marine mammal experts believed that toothed whales followed a do-as-mother-does
model for foraging techniques, maintaining tight bonds for at least two years. However, prior research in Shark Bay—conducted between 2007 and 2018 across more than 5,278 encounters involving over 1,035 individual Indo-Pacific bottlenose dolphins—concluded that shelling behaviours spread primarily through horizontal peer networks rather than direct maternal instruction.
The recent Queensland observations complicate that narrative. In the recorded sequence, an adult female surfaced with a shell, dropped it when the fish escaped, and chased the prey down. Within minutes, her calf retrieved the same shell and attempted the maneuver.
“Our footage challenges the belief that dolphins learn this tool strictly from their peers. These findings highlight just how smart, clever, and innovative dolphins are.”
Dr Alexis Levengood, lead author and animal behaviourist
Independent Innovation Across Distant Populations
The geographical separation between the Hervey Bay and Shark Bay populations points toward independent cultural innovation. According to research teams studying Australian cetaceans, marine mammals separated by thousands of kilometres have developed identical tool-use strategies without cross-population contact.
Researchers note that mastering shelling requires a high degree of physical dexterity and ecological knowledge. The technique depends on locating empty gastropod shells of a sufficient size, positioning the body correctly underwater, and executing a rapid surface shake.
Environmental pressures may also play a role in the emergence of these tactics. Prior scientific literature points to extreme environmental shifts—such as marine heatwaves that decimate seagrass habitats and trigger invertebrate die-offs—which can temporarily increase the availability of large, empty shells on the seafloor and encourage novel foraging experimentation.
Evaluating Tool Use Among Long-Lived Mammals
Tool use remains exceedingly rare among non-human animals. Beyond shelling and sponge use—where dolphins cover their beaks with basket sponges torn from the seafloor to protect their snouts from stings and abrasive sand—cetaceans exhibit few documented technological innovations.
Comparative analyses often group dolphins alongside great apes, including chimpanzees, gorillas, and humans. Despite divergent evolutionary paths and vastly different aquatic and terrestrial environments, both groups feature long-lived, large-brained mammals capable of high innovation and the cultural transmission of acquired skills.
Scientists emphasize that shelling events are likely underreported. The shell-shaking sequence lasts only a few seconds, making discrete foraging episodes easy to miss during routine boat surveys. Some individual animals incorporate shells into their daily foraging routine regularly, while others are spotted using them only once.
Unresolved Questions in Marine Mammal Behaviour
Despite the recent breakthroughs in the Great Sandy Marine Park, marine biologists caution that significant gaps remain in understanding the mechanics of cetacean tool use.
As scientists gather more data on animal tool use, the findings continue to refine our understanding of how high cognitive capacity evolves independently across vastly different species.
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