Dolphins echolocate with two-part acoustic beams. Dr Josefin Starkhammar of Lund University explains how this could help us improve ultrasound technology.
Why do dolphins need echolocation?
They use it for navigation, hunting for prey and possibly in social contexts. Dolphins always use acoustics as their primary sense. They generate short sound pulses, which bounce off surfaces and come back as echoes – the time it takes to return is a measure of how far away an object is. The beam is quite focused so the dolphins turn their heads to scan their environment.
How do they produce acoustic beams?
They have a structure below the blowhole called the phonic lips. Sounds come out through the melon, the rounded forehead – it’s one of the tissues responsible for the shape and formation of the beam. It’s basically an acoustic lens: the speed of sound is faster along the edges compared to the core of the melon, so the beam ends up cone-shaped. Dolphins have extremely short signals, usually much shorter than bats.
Denne historien er fra December 2018-utgaven av BBC Earth.
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Denne historien er fra December 2018-utgaven av BBC Earth.
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