Researchers from the United States National Marine Mammal Foundation have released new footage captured from the view of freely hunting dolphins along North American coastal waters. The findings are discussed in a study published in PLOS ONE.
In a related scientific effort reported last year, researchers with the US Navy fitted cameras to captive dolphins trained to detect underwater mines, then released them to hunt within San Diego Bay. The goal was to observe how these intelligent creatures work in real hunting scenarios and how their behavior adapts to natural environments.
The study notes that some dolphins displayed a surprising level of independence, with a few choosing to roam, but the majority stayed within the study area, continuing their tasks and routines as the researchers observed. The team collected a wealth of video, photographic, and audio data to build a comprehensive picture of the dolphin’s hunting process.
The dolphins emitted rapid clicks at intervals ranging roughly from 20 to 50 milliseconds while pursuing prey. As the hunt intensified, the clicking pattern shifted toward a buzz, and then to a higher-pitched squeal. When in direct contact with prey, the sound intensified further, remaining both constant and rapid until the fish was captured.
Across the footage, the dolphins brought in more than 200 fish, including various species such as perch, croaker, flounder, smelt, and an unusual entry listed as marine igloo. The researchers observed that the hunt reached a peak level of signaling and movement as the fish attempted to evade, illustrating the sophisticated coordination of the dolphins in a naturalistic setting.
Among the recorded events, one striking moment involved a dolphin capturing eight highly venomous yellow-bellied sea snakes (hydrophis platurus). Scientists have suggested that this behavior could reflect differences in hunting experience, particularly for dolphins raised in captivity who might lack the same opportunities to hunt in social groups as wild individuals. The observations underscore how social dynamics, learning, and environmental context shape hunting strategies in these marine mammals.