Researchers at SpeakDolphin.com are claiming to have bridged that gap between humans and dolphins for the very first time. Dolphin biosonar works by releasing a series of high-frequency “clicks” from an organ in their skulls known as a melon. As the click passes through the water, it encounters objects. These objects generate a return signal that the dolphin receives and interprets. If you’ve ever stood near a building or large surface and heard the way it affected your voice, or heard an actual echo chamber in action, you’ve experienced a crude example of what dolphins can perform biologically at much higher resolution.


The research team created the image below in two steps. First, it used high-test audio equipment to capture the sonic vibrations produced by Amaya (the dolphin) as she swept her biosonar across various objects. Because any object in the water attenuates the original signal, measuring how these signals differ can give us the idea of a shape of an object. The technique seems similar to looking at a shadow cast on a wall to get a sense of the person casting it.
The team tested a variety of objects, including a flower pot and cube, before finally testing a human. The diver, Jim McDonough, swam without breathing gear to make certain that air bubbles didn’t impact the final image. McDonough submerged himself in front of the dolphin, Amaya, who scanned him with her biosonar. The research team then relayed their audio measurements to the CymaScope lab in the UK. A CymaScope is a device capable of projecting sonic vibrations into pure water and measuring the result.

http://sneapsky..com/2015/12/revealed-how-dolphins-see-people-via.html