Human high-pitch clicks

Jamie Aspland uses an 'echo location' technique, uttering high-pitch clicks with the sound then rebounding off surfaces to help guide him round obstacles.
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The four-year-old, who was born without his sight, was taught the technique as part of a revolutionary new scheme in the US to help the blind.
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His mother Deborah, 39, hailed the treatment after her son was able to walk unaided to the park for the first time and steered himself around a fence he was heading straight for.
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Speaking after just three sessions of the therapy, she said: It's changed our lives.
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The therapy has been a revelation.
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Since learning the skill we can walk to the park and Jamie no longer has to hold my hand.
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He even clicks to find out where the handrails are on our staircase before walking down unaided - it's amazing.
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Jamie, from Ashford in Kent, has just completed his third session with US-based guru Daniel Kish - who lost his sight when he was just 13 months old.
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As president of World Access for the Blind, Mr Kish has developed a system based on animal sonar to help humans form mental maps of their surroundings.
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He copied the technique dolphins use to navigate their way through the murky depths - using high pitch clicks to penetrate objects and reflect off their internal structure.
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Jamie is able to mirror that behaviour - which complements his use of a cane - by flicking his tongue against the roof of his mouth.
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When the sound waves hit an object, it reflects the energy back to the ear to enable a blind person to decode its size, shape and distance.
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A tree may be detectable and recognized at 10 metres, while a large building may be detectable at 100 metres or more.
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It is literally like 'seeing' with dim flashes of light. In fact, neural scientists believe that the same parts of the brain used in visual processing are also being deployed for FlashSonar.
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Ms Aspland, a mother-of-three, gave up her job as a tour operator to care for Jamie, his twin sister Rosie, who also has learning difficulties, and their autistic brother Kane full time.
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She said she watched nervously after Jamie's first session when he approached a fence - but he managed to walk round it.
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We thought he was going to go straight into it.
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But he just went round it - I didn't think it would be possible.
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He was born blind but this therapy has given him a new lease of life
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Telegraph