New research reveals how dolphins see people via echolocation

One of the most profound barriers between humans and other species of life on Earth is understanding how they perceive the world. This is particularly true with aquatic species, which have adapted to life in an entirely different environment than our own. We’ve known for decades that dolphins could use echolocation to avoid objects and hunt for food, but knowing that a capability exists is a far cry from understanding how the animal perceives its own capability.
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.

Dolphin sonar. Image by Wikipedia

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. Such results can then be turned into a representation of a physical object or objects, as shown below:

It’s important to note that the resulting image doesn’t tell us how a dolphin perceives the input it receives from its sonar. The brain plays a substantial role in interpreting the information gathered by our various senses, and dolphins have a very different ear structure than our own. The dolphin brain devotes a much higher proportion of its area to sound processing than our own does. There’s still a profound barrier between a human representation of what a dolphin can see and an actual understanding of what a dolphin “sees.”
Even allowing for this, Speakdolphin.com has racked up a very cool achievement. It’s unlikely that we’ll ever be able to fully understand the perceptions of a creature so different from us — but experiments like this may help us convert what animals experience into something we can understand. As translations go, it’s a great start.