A small population of dolphins in Shark Bay in Western Australia have a documented history of using an unusual tool to help them catch fish: Large, empty snail shells. For the first time, scientists have now observed the same behavior in a different dolphin population on Australia’s east coast.
Researchers even filmed a baby dolphin and its mother using a shell to capture fish, suggesting the baby may have learned the skill from its mother — this hadn’t been observed before now, they write in a recent study.
“The second I saw it [on the east coast], I was like, oh my God, oh my God, oh my God, this is huge,” study lead author Alexis Levengood, a lecturer of animal ecology at the University of the Sunshine Coast, Australia, told Mongabay in a video call.
In a behavior called “shelling,” bottlenose dolphins (Tursiops truncatus) can chase fish into large empty sea snail shells, stick their beak inside to trap the fish, and then raise the shell to the water’s surface where the fish slides out into the dolphin’s mouth.
“It essentially gives them a competitive edge over other dolphins that aren’t using this type of tool use because it makes it easier for them to catch harder-to-catch fish,” Levengood said.
The behavior was first described in 2011 when researchers found roughly 2% of dolphins in Shark Bay demonstrated the skill. It was believed to be a localized behavior until Levengood confirmed three dolphins in Great Sandy Marine Park, Queensland, using the same technique in 2025. The researchers note that photographers aboard a tour boat took photos of dolphins shelling in the same area in 2013 and 2019.
The two dolphin populations on opposite sides of Australia don’t migrate, so the Queensland dolphins couldn’t have directly learned the skill from the Shark Bay population, Levengood said.
She added that while it’s possible the behavior is common, but not observed by trained scientists, their “leading theory is that it’s independently innovated.”
Both dolphin populations live in bays with shallow water and large gastropod shells — the right environments to innovate “shelling,” Levengood said.
In Shark Bay, scientists believe dolphins learned the behavior from peers. In Great Sandy Marine Park, Levengood’s team observed a dolphin calf repeat the behavior immediately after its mother.
“It’s pretty exciting because it gives us a different insight into how this is learned,” Levengood said.
Some dolphins are also known to put sea sponges on their beaks to protect delicate skin while foraging on the rocky seafloor. “Sponging” is a challenging skill, Levengood said, and one that dolphins can only learn from their mothers as babies. “Shelling” is easier to master and can be learned as a baby from mom or from peers later in life.
Levengood said such behavioral flexibility “shows how incredibly intelligent the dolphins are.”
Banner image: An adult dolphin “shelling.” Image courtesy of the University of the Sunshine Coast Australia.
