The dolphin's silver rings...

Before you see the video, please read:


The film shows some dolphins playing with silver rings of air, which themselves have the ability to do under water.
We do not know how they learned, or are an innate ability.
As if by magic the dolphin does a quick flicker appears with the head and a silver ring and in front of the nozzle. It is like a bubble of air that does not rise to surface. It remains under water as a door to an invisible magical dimension.
One explanation for the phenomenon says that the invisible vortices are generated from revolving dolphin's back when he moves quickly and turns.
When the dolphins break the line, the tips are attracted to a closed ring.
The high of fluid speed around the vortex centre is at lower pressure than the fluid circulating farther away.
It is injected air bubbles in the rings by released through the hole which the dolphin expels the air.
The energy of the water vortex is sufficient to avoid the bubbles that rise during the last games seconds.

Well, if it was possible to understand, great.
Otherwise, let it go there and delight with the images of these magnificent creatures.