Dolphin Address 1 2003
9 juni 2003
When I look at a sharp close-up of a dolphins head in clear water I no seldom see very fine vibration lines and other shades of light refraction that seem to have little to do with the vortexes caused by the displacement of the dolphin.
For a long time it remained a lonely observation that only on occasion went looking for an explanation. Until, just for fun, I started to (lip)whistle back when my kettle water boiled. Especially when I turned off the gas and the tone of the whistle ran back, my whistle began to interfere with it. Moreover, the compound sound seemed to start leading a life of its own, that was only influence able in intervals.
This bore me the thought, that dolphins do not use one type of sound to reap info out of the echo, but two. Next to the outgoing sound, that is reverberated as echo, a receptive sound seems to be evoked, that, as an acoustic band around the rostrum, is sounding out the echo by variations in pitch.
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The accompanying photo I made just off the pondrock at Pollenawatch as a test picture to finger out my digital camera. Especially when you zoom in, the refined wealth of figure that graces Dusty's head becomes apparent. Here she lies romping with Brian who almost lost his flipper fin. There was quite a swell about, that nearly threw her against the rock. Upon the pondrock five people were yelling, whistling, photographing and filming. That is quite a lot to keep an 'eye' on for one dolphin. But that's the kind of queen she is and this is her Tiara.
Jan Ploeg, Lisdoonvarna, June 9th 2003
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