Common bottlenose dolphin Bubbles targets schools of Bigeye Trevally on shallow reefs off Lady Elliot Island, harassing individual fish until they regurgitate their food before consuming the remains, according to University of the Sunshine Coast researchers. The behaviour, documented between 2021 and 2025 and published in Ecology and Evolution, represents the first detailed description of kleptoparasitism in a cetacean anywhere in the world.
University of the Sunshine Coast Researchers Document Novel Foraging Strategy
According to co-authors Dr Asia Haines and PhD student Romney Edwards-Francis, Bubbles was observed utilizing the food-stealing tactic 11 times in the southern Great Barrier Reef. Researchers state the dolphin repeatedly chases selected fish from a school until the prey expels its stomach contents due to the stress response. Dr Haines notes that observing the animal repeat this tactic over several years suggests he has learned to target fish carrying the fullest bellies for the most rewarding meals.
The research team hypothesizes that Bubbles amplifies the stress response of the trevally by using intense repeated clicking and low-pitched vocalisations during the chase. Ms Edwards-Francis explains that this specialised foraging technique likely helps the dolphin avoid the energy cost of catching his own food, particularly because common bottlenose dolphins typically forage in groups while Bubbles was always observed foraging alone.
Did you know? While dolphins are widely perceived as friendly, smiling creatures, researchers emphasize that this is largely anthropomorphism. Dr Haines points out that dolphins are predators that actively hunt their prey, regardless of whether they catch it themselves or steal it from other species.
Implications for Marine Research and Cetacean Adaptability
The documentation of Bubbles’ behaviour highlights the adaptability and flexibility of common bottlenose dolphins when it comes to foraging strategies. According to Ms Edwards-Francis, rare or novel tactics like kleptoparasitism are likely underreported in dolphins or other cetaceans due to the inherent difficulties of monitoring the animals underwater over longer time periods. Researchers suggest that combining emerging technologies such as drones with underwater surveys may provide a way to overcome this.
The findings form part of the broader UniSC-led Leaf to Reef project, which conducts long-term ecological monitoring and research on and around Lady Elliot Island with backing from the Great Barrier Reef Foundation’s Reef Islands Initiative.
Frequently Asked Questions
What is kleptoparasitism in marine mammals?
Kleptoparasitism is a feeding strategy where an animal steals food caught or collected by another. According to University of the Sunshine Coast researchers, documenting this behaviour in a cetacean is a first detailed description anywhere in the world.
How does the dolphin steal the food?
According to study authors Dr Asia Haines and Romney Edwards-Francis, Bubbles targets schools of Bigeye Trevally, chases an individual fish until it regurgitates its food due to stress, and then eats the expelled remains.
Is this behavior common among common bottlenose dolphins?
Researchers note that while Bubbles’ actions demonstrate species adaptability, such tactics are likely underreported in dolphins or other cetaceans because monitoring the animals underwater over longer time periods is challenging.
Where was this behavior documented?
According to the published findings, the observations took place between 2021 and 2025 in shallow reefs off Lady Elliot Island in the southern Great Barrier Reef.
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