The US Navy equipped some dolphins with cameras and allowed them to swim in the open sea. It was planned to observe how they ate.
Six bottlenose dolphins from the US National Marine Mammal Foundation were chosen for this investigation (NMMF). These dolphins had cameras attached to them, and they were tracked for six months. In San Diego Bay, the dolphins were permitted to hunt at will.
The video showed some fascinating things. The dolphins were pursuing their prey for a very long time and even had deadly snakes in their sights.
These dolphins from NMMF were captive dolphins, although they were accustomed to oceanic hunting. As a result, it was believed that their hunting instincts were comparable to those of their oceanic counterparts in the wild.
The researchers have published their findings in the PLOS One publication.
The researchers report that dolphins ‘clicked practically continuously as they searched at intervals of 20 to 50 milliseconds.’
‘Click intervals become shorter as the prey gets closer, eventually morphing into a terminal buzz and a shriek. Fish contact resulted in buzzing and shrieking that continued virtually nonstop until the fish was swallowed.’
The researchers go on to explain that these dolphins ‘appeared to employ both sight and hearing to find prey.’
‘The dolphins always used echolocation to locate fish from a distance. Close up, it looked that echolocation and eyesight were employed in tandem.’