Spinner dolphin (photo: Julien Stein/Marine Photobank)

Dolphins and their amazing echolocation

Last night we watched the third episode of the BBC’s famous Ocean Giants series. Voices of the Sea featured whales and dolphins and explored what we know about the vocalisations they make.

Moon Pool draws a great deal on what is known about dolphin vocalization, the way they use echolocation to find their prey and to orientate themselves. Among the many amazing things dolphins can do is to eavesdrop each other’s echolocation.

Grab a thinking doughnut and get your teeth round this. Imagine you are out walking with a group of friends and you see something interesting. Right now, you can either tell the others what you want them to look at or you can point. But what if you could send a message that not only told them where to look but also explained how large and how thick the object was and even gave an idea of its texture? Imagine you could do that even though the object was hidden beneath ten centimetres of sand and even though it was pitch dark.

That’s what dolphins can do with their echolocation, not by talking but by firing off a burst of clicks that other dolphins can intercept and decode. In many ways this is a shorthand language without words. Echolocation helps whales and dolphins map the world around them, to avoid obstacles or threats, as well as to help them find food or to locate each other.

Bottlenose dolphin (photo: NASA)

For narwhals, swimming under the ice in the arctic during winter, echolocation is vital to their survival. Without their echolocation ability, to help them locate holes in the ice sheet, they would quickly die of suffocation, unable to gain access to the open air to breathe.


Boto - Amazon River dolphins

This same ability is used by the Amazon river dolphin, or Boto, to find food in the murky waters it inhabits. In fact, echolocation is much more important to the Boto than its eyes when it comes to finding food.

Botos, and other dolphins, use two separate sound systems simultaneously, talking to each other and using their echolocation to get around. Boto echolocation is so sensitive that they can spot objects as small as a pin. Their brain capacity is 40% larger than that of humans.


A melon isn't just a fruit

The dome-shaped forehead of dolphins and whales conceal the secret to their echolocation skills, though the composition and shape of the melon varies hugely between different species of dolphin and whales. The beluga whale is even able to change the shape of its melon at will. This is thought to change the size, shape, direction and frequency of the echolocation beam, to enable it to ‘see’ in different ways.

Body language is also hugely important in dolphins, as we see in Moon Pool. The way in which dolphins position themselves in the water or angle their flippers, for example, all play a part in communication, much as humans convey meaning with their eyebrows, hand gestures, facial grimaces and body postures.


The amazing dolphins of Laguna

One source of inspiration for we are POD is found in Brazil. Off the coast of Laguna, dolphins and fishermen have been working together to catch fish for well over a hundred years. By working together humans and dolphins both benefit. They have developed a mutually intelligible language to help them and humans and dolphins have been teaching their offspring this common language for generations.


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