I ran across this and found it quite fascinating.
Video of Dolphins at Play - Photobucket - Video and Image Hosting
Humans blow smoke rings but dolphins have a much healthier habit. The
attached video is of dolphins playing with 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 rings, 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.
Video of Dolphins at Play - Photobucket - Video and Image Hosting
Humans blow smoke rings but dolphins have a much healthier habit. The
attached video is of dolphins playing with 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 rings, 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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