Dolphin Address 30 2003
September 10, 2003
Humans do not reflect breathing. For a dolphin this is much more sensitive. Dusty always has to find a position in which to breathe. When the sea is calm this is not much of a problem. She can stay under water for about 8 minutes, so she just has to surface. In a storm this seems a lot harder. But if she can jump out of the water it should hardly be a problem to emerge a little higher. In this she has a refined ability at her disposal to observe the surface. With the surrounding tissue of her blowhole she can fathom the water pressure.
Experienced snorkel divers are aware of this: at an ascent you feel the moment coming that you can empty your snorkel and particularly that you can take in new air. It is a hard way learning. A premature discharge will fill up the snorkel again and you will have no breath left to empty it for the second time. By all means you will not be able to draw new breath. The only escape is to take the snorkel out of your mouth and somehow or other reach for air.
But I think she literally has a back-up check. Often she swims so close to the surface that she cuts through it with the top of her fin. From underneath you see the light refracting to a trace. The dorsal fin does not only both keep a 'keel' course and facilitates leaving the surface. It is also a 'shallow' meter with 'side-wave' sensitivity. The combination with the sensitivity of the blowhole tissue yields an ascend/descend relation that monitors her position towards the surface undulation. Converted to human conditions and corrected to a vertical, gravity bound existence, it adds up to balance: the shake between for- and backward.
In quiet weather she often breathes with her body in such a curve, that the leading edge of her dorsal fin, in side view, is continuative. In higher waves I can show on video how she first slows down with her fluke to take position and further nearly ascends horizontally in order to breathe.
Exhale she can at all times, but in this she seems economical. Sometimes she releases strings of small bubbles, seldom bigger ones and more often a lot at once. I think she needs a 'basic' filling, a minimal pressure for breathing in fast. Because of the very limited time that avails her, this must be an elastic movement. Therefore the power of expulsion is related to the capacity of capture.
I'm happy to be strong. Swimming with Dusty yields a surprising inspiration: I can hold my breath for comfortably two times normal. But it costs very much power and when out of the water, I again feel the grim pull of gravity. I swab on my legs for the first few minutes. Fortunately I do have a very light head then.
Jan Ploeg, Fanore meadow, September 10th 2003
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