A Great Barrier Reef dolphin chased trevally into regurgitating in 11 of 20 recorded encounters

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 ^[7]. 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 ^[25].

The 20 records span about 52 months, roughly one every two and a half months ^[8]. 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 ^[14][24].

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 ^[15]. Both published accounts present this as a hypothesis ^[15].

The team never saw him eat a trevally ^[12]. He held onto his chosen fish across a trip to the surface for air, then went back to the same one ^[11]. In one half-hour he ran the sequence up to 10 times ^[10].

"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 ^[16]. 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 ^[13]. 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 ^[23]. "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 ^[17]. 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 ^[18]. 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" ^[19]. 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 ^[20].

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 ^[26]. "Dolphins are predators and actively hunt their prey, whether it has been stolen from another species or not," she said ^[21].