A Great Barrier Reef dolphin chased trevally into regurgitating in 11 of 20 recorded encounters
University of the Sunshine Coast researchers call it the first detailed description of kleptoparasitism in any cetacean. The evidence is one identifiable animal across 20 logged encounters in four years, and no one has measured the energy saving.
The Scientist · Science desk
What happened
- University of the Sunshine Coast researchers published their observations of a common bottlenose dolphin nicknamed Bubbles in the journal Ecology and Evolution.
- In each case he clicked and swung his head across the school, singled out one trevally, chased it at close range until it regurgitated, ate the expelled food, and went back for another.
- Notches in his dorsal fin and a V-shaped scar on his right side let the researchers confirm that every record involved the same individual dolphin.
Why it matters
- What it limits constraint With one animal and no energy measurements, the efficiency explanation stays a hypothesis: nobody has compared the calories a chase costs against the calories it returns.
- What doesn't add up contradiction Phys.org reports the first detailed description in any cetacean and Discover reports some of the first evidence; the difference decides whether readers are being told about new behaviour or newly recorded behaviour.
- What's now possible capability Because Bubbles can be recognised from fin notches and a scar, any diver at Lady Elliot Island can add to the same individual's file, so the learned-strategy claim is testable by continued watching.
- What it sets up precedent The paper sets the reference case: the next report of a cetacean stealing another animal's meal will be weighed against 11 documented events over four years.
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The team logged 20 records of Bubbles working schools of bigeye trevally between June 2021 and October 2025, and in 11 of them he fed on food a fish had brought up [5]. So 55 percent of logged encounters ended in a stolen meal [15]. That figure applies to logged encounters only. Edwards-Francis said feeding habits like his can go unnoticed because it is hard to follow an animal underwater long enough to see everything it does [10].
The 20 records span about 52 months, roughly one every two and a half months [22]. That spacing is a property of when divers were in the water at a reef resort site. Resort staff had been seeing Bubbles since at least 2017, four years before the study's first record [21][23].
The explanation offered for the vomiting is the trevally's own stress reaction to being chased at close range, and the researchers suspect his repeated clicks and low-pitched calls push that stress higher [7]. Both published accounts present this as a hypothesis [7].
The team never saw him eat a trevally [19]. He held onto his chosen fish across a trip to the surface for air, then went back to the same one [13]. In one half-hour he ran the sequence up to 10 times [12].
"We observed him repeating this behavior over several years, which suggests he may have learned to target the fish with the fullest bellies, providing the most rewarding meals," Haines said [24]. The repetition is what separates this from a one-off event, and it rests on the identification: notches in his dorsal fin and a V-shaped scar on his right side [20]. With one animal, a tactic learned from another dolphin looks the same as one invented once.
The energy story is an inference. Edwards-Francis said the team believed the habit might spare him the cost of catching his own food [26]. "Common bottlenose dolphins tend to forage in groups, yet Bubbles was always observed foraging alone. It may be that this specialized tactic requires less energy than directly pursuing fast-moving prey, particularly when foraging solo," she said [25]. The published accounts do not report the cost of a chase or the contents of a trevally's stomach.
Haines said kleptoparasitism is a common strategy across animals, usually opportunistic, and rarely documented in aquatic species and marine mammals in particular [14]. So the scarcity could be either kind: rare in nature, or rare in the literature. Edwards-Francis said, "We also suspect that rare or novel foraging tactics such as kleptoparasitism are likely underreported in dolphins or other cetaceans" [8]. On the evidence given, I would call this a well-documented habit in one individual, and it stops short of a species-level strategy.
"The challenge is monitoring the animals underwater over longer time periods to capture their full range of behaviors. Combining emerging technologies such as drones with underwater surveys may provide a way to overcome this," Edwards-Francis said [9].
Haines rejected the idea that any of this dents the animal's reputation, which she put down to anthropomorphism and to the fact that dolphins appear to be smiling [18]. "Dolphins are predators and actively hunt their prey, whether it has been stolen from another species or not," she said [16].
What to watch
- A second identified cetacean, anywhere, chasing prey into regurgitating would move this from one animal's habit toward a species tactic.
- Any test of the stress hypothesis, such as measuring what a chased trevally does physiologically, would replace an inference with data.
- Earlier records of cetacean food theft surfacing in the literature would soften the 'first detailed description' framing.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence55
- Adoption
- Not scored
- Hype gap+20
- Incentives
- Not scored
- Confidence60
Perspective Coverage
3 publishers- Builder
- Builder 53%
- Operator
- Operator 42%
- Investor
- Investor 5%
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
University of the Sunshine Coast researchers documented the feeding behaviour of a common bottlenose dolphin nicknamed Bubbles off Lady Elliot Island, in the southern Great Barrier Reef.
- [2]
The findings were published in Ecology and Evolution as Romney Edwards-Francis et al, 'Repeated Observations Suggesting Kleptoparasitism by a Common Bottlenose Dolphin (Tursiops truncatus) on the Great Barrier Reef', DOI 10.1002/ece3.74270.
- [3]
Co-authors Dr Asia Haines and UniSC PhD student Romney Edwards-Francis say the behaviour represents the first detailed description of kleptoparasitism in a cetacean anywhere in the world.
- [4]
Discover magazine describes the study as reporting what the researchers consider some of the first evidence of kleptoparasitism in a dolphin or any other cetacean.
- [5]
Between June 2021 and October 2025 the team gathered 20 records of Bubbles interacting with schools of bigeye trevally, and in 11 of them he ate food a fish had thrown up.
- [6]
Between 2021 and 2025 researchers observed and videotaped Bubbles' kleptoparasitic behaviour 11 times in shallow reefs off Lady Elliot Island.
- [7]
The researchers say Bubbles appears to take advantage of the fish's stress response to being chased, and hypothesise that he may also use intense, repeated clicking and low-pitched vocalisations to heighten stress levels.
- [8]
"We also suspect that rare or novel foraging tactics such as kleptoparasitism are likely underreported in dolphins or other cetaceans," Edwards-Francis said.
- [9]
"The challenge is monitoring the animals underwater over longer time periods to capture their full range of behaviors. Combining emerging technologies such as drones with underwater surveys may provide a way to overcome this," Edwards-Francis said.
- [10]
Edwards-Francis said feeding habits like Bubbles's could go unnoticed because it is difficult to follow animals underwater for long enough to see everything they get up to.
- [11]
Bubbles moved his head from side to side while making echolocation clicks, apparently scanning the school, then singled out one trevally, separated it and tracked it, sped up and chased it at close range until it threw up, ate the expelled food while the fish swam away, and returned to the school.
- [12]
Researchers recorded Bubbles repeating the sequence up to 10 times in half an hour.
- [13]
Bubbles seemed to stick with his chosen fish even when he had to surface for a breath, returning to chase the same one afterward.
- [14]
Haines said that while kleptoparasitism was a common feeding strategy used by many animals to steal food caught or collected by another, it was usually opportunistic and had rarely been documented in aquatic species, particularly marine mammals.
- [15]
The 11 feeding events represent 55 percent of the 20 logged encounters with trevally schools.
- [16]
"Dolphins are predators and actively hunt their prey, whether it has been stolen from another species or not," Haines said.
- [17]
Common bottlenose dolphins often hunt in groups, but Bubbles was on his own each time he was recorded stealing a meal.
- [18]
Haines attributed the perception of dolphins as the 'good guys of the sea' to anthropomorphism, our tendency to assign human characteristics to them, and perhaps to the fact that dolphins appear to be smiling.
- [19]
Throughout the encounters, the researchers never saw Bubbles eat the trevally themselves.
- [20]
Notches in his dorsal fin and a V-shaped scar on his right side helped researchers confirm they were watching the same dolphin.
- [21]
Resort staff had been seeing Bubbles around Lady Elliot Island since at least 2017.
- [22]
June 2021 to October 2025 is 52 months, so 20 records average one recorded encounter every 2.6 months.
- [23]
The first resort-staff sightings in 2017 precede the study's first record in June 2021 by about four years.
- [24]
"We observed him repeating this behavior over several years, which suggests he may have learned to target the fish with the fullest bellies, providing the most rewarding meals," Haines said.
- [25]
"Common bottlenose dolphins tend to forage in groups, yet Bubbles was always observed foraging alone. It may be that this specialized tactic requires less energy than directly pursuing fast-moving prey, particularly when foraging solo," she said.
- [26]
Edwards-Francis said the research team believed Bubbles' thieving tendencies might help him avoid the energy cost of catching his own food by letting other animals do the hard work for him.
Sources
3 independent publishers whose own reporting we read for this story.
- discovermagazine.comA Bottlenose Dolphin Named Bubbles Chases Fish Until They Throw Up, Then Steals Their Meals
1 article · September 16, 2026
- phys.orgBubbles the food-stealing dolphin finds shortcut to easy meal
1 article · September 15, 2026
- scientificamerican.comThis dolphin terrifies fish until they puke—and then it eats their upchuck
1 article · September 18, 2026
Topics and entities
Topics
- Cetacean behaviour
- Kleptoparasitism
Entities
- Great Barrier Reef
- University of the Sunshine Coast
- Ecology and Evolution
- Romney Edwards-Francis
- Common bottlenose dolphin
- Lady Elliot Island