East Coast dolphins independently adopt shellfish hunting technique

Eastern Australia’s bottlenose dolphins have learned to catch fish using large shells, ERR reports. Researchers say the behaviour represents an independent innovation by a population separated by thousands of kilometres from dolphins on Australia’s western coast.

Small fish hide in empty shells on the seabed. The dolphins pick up the shells underwater and shake them at the surface, causing the fish to slide out of the opening and into their mouths. Scientists call the technique shelling.

Shelling requires considerable skill and precise handling of the object used as a tool. Marine biologists previously believed that the behaviour was practised only by bottlenose dolphins in Shark Bay on Australia’s western coast. Even there, fewer than 2% of the population use empty shells in this way.

Researchers have now observed the same behaviour in Hervey Bay, in the Great Sandy Marine Park on Australia’s east coast. They say the finding suggests that two completely isolated populations have independently arrived at the same solution for obtaining food.

Tool use can reduce competition for food and allow more resourceful animals to feed in places or situations where conventional methods do not work. It may also help marine mammals occupy new ecological niches and ease competition between members of the same species.

Learning from the mother

Local ecotourism guides photographed east coast dolphins using the technique in 2013 and 2019. Scientists formally confirmed the behaviour in the summer of 2025, when biologists made the first official observation from their research vessel.

One rainy July morning, the researchers saw an adult female bottlenose dolphin moving a large shell at the water’s surface. The observation lasted only nine minutes because of the rain. The female lifted the heavy shell from the water several times with the tip of her snout before briefly manoeuvring it and allowing it to sink.

A few months later, a drone recorded another female and her calf feeding in shallow water. The mother brought a large shell up from the seabed, and a small fish slipped out of its opening. When the fish unexpectedly escaped, the female dropped the shell and chased it.

Immediately after the mother moved away, her calf picked up the shell. The young dolphin held it in exactly the same way as its mother and struck it against the water’s surface several times. After briefly experimenting, it swam back to its mother. Researchers said this direct imitation was particularly noteworthy.

The recording suggests that the skill may pass directly from mother to offspring, indicating vertical social learning. More cases are needed to confirm how widespread this behaviour is.