Scientists from the US National Marine Mammal Foundation have released new photos taken from the perspective of freely hunting dolphins off the coast of North America. Research published in the journal PLOS ONE.
For a scientific study published last year, the US Navy attached cameras to captive dolphins trained to recognize underwater mines and then released them to hunt in San Diego Bay.
“They could sail if they wanted to, and over the years some did. But almost all of them remained,” the authors write.
The scientists took video, photo and audio recordings. Dolphins clicked almost continuously at intervals of 20 to 50 milliseconds while hunting,” they wrote in their article. When approaching its prey, the intervals between clicks were reduced to a buzz, and then to a squeak. In contact with the fish, the buzz and screech was almost constant until the fish was swallowed.
The dolphins caught more than 200 fish, including perch, croaker, flounder, smelt, and marine igloo. Smelt would often throw himself into the air in a desperate attempt to evade skilled predators.
A dolphin ate eight highly venomous yellow-bellied sea snakes (hydrophis platurus). Scientists believe this may be due to the fact that dolphins are kept in captivity and therefore do not have experience hunting with other individuals.