[CINC] Dolphins' Magic Rings

[Deborah Lee Clark]

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 Does anyone know about this? I received an amazing video which I will gladly forward to anyone who wants it-too big for the rain list.
Deb Clark
 
Here's the explanation that came with it:
> The attached video is of  dolphins playing with silver colored rings
> which they have the ability to make under water to play with.  It  
> isn't
> known how they learn this, or if it's an inbred ability.
>
> As if by magic the dolphin does a quick flip of its head and a  
> silver ring
> appears in front of its pointed beak. The ring is a solid, donut
> shaped bubble about 2-ft across, yet it doesn't rise to the surface  
> of the
> water!  It stands upright in the water like a magic doorway to an  
> unseen
> dimension. The dolphin then pulls a small silver donut from the  
> larger one.
> Looking at  the twisting ring for one last time a bite is taken from  
> it,
> causing the small ring to collapse into a thousands of tiny bubbles  
> which
> head upward towards the water's surface.  After a few moments the
> dolphin creates another ring to play with.  There also seems to be a
> separate mechanism for producing small ring which a dolphin can  
> accomplish
> by a quick flip of its head.
>
> An explanation of how dolphins make these silver rings is that they
> are 'air-core vortex rings'.  Invisible, spinning vortices in the  
> water are
> generated from the tip of a dolphin's dorsal fin when it is moving  
> rapidly
> and turning. When dolphins break the line, the ends are drawn  
> together into
> a closed ring.  The higher velocity fluid around the core of the  
> vortex is
> at a lower pressure than the fluid circulating farther away. Air is  
> injected
> into the rings via bubbles released from the dolphin's blowhole. The  
> energy
> of the water vortex is enough to keep the bubbles from rising for a
> reasonably few seconds of play time.






 
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