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Mystery
of the Silver Rings The young dolphin gives a quick flip of her
head, and an undulating silver ring appears--as if by magic--in front of
her. The ring is a solid, toroidal bubble two feet across--and yet it
does not rise to the surface! It stands erect in the water like the rim
of a magic mirror, or the doorway to an unseen dimension. For long
seconds the dolphin regards its creation, from varying aspects and
angles, with its vision and sonar. Seemingly making a judgement, the
dolphin then quickly pulls a small silver donut from the larger
structure, which collapses into small bubbles. She then
"pushes" the donut, which stays just inches ahead of her
rostrum, perhaps 20 feet over a period of up to 10 seconds. Then,
stopping again, she regards the twisting ring for a last time and bites
it--causing it to collapse into a thousand tiny bubbles which head--as
they should--for the water's surface. After a few moments of reflection,
she creates another. This isn't fantasy, it's real. And it isn't
magic, just marvelous. It is a rare dolphin behavior, and we first saw
it in the play of two baby dolphins. It gives us a little more insight
into the superb level of control dolphins can exercise on their water
environment, and underscores the fact that we can still discover things
about dolphins by simply watching them. I first saw this behavior on one of my
relatively rare trips out to the Delphis lab; the project's principle
scientist Ken Marten said that "the two babies, Tinkerbell and Maui"
had been doing it for a little while. My reaction: "Wow, neato. How
the heck do they DO that? Try to get some photo and video shots of it.
It sure is cool". Ken, along with Suchi Psarakos, Research
Assistant and computer programmer, did indeed document the silver rings
(although video and photos don't do the rings justice), and this has
made it possible to both analyze the physics behind the phenomenon and
to watch the dolphins do this trick in slow-motion. As it turned out, small silver rings weren't the
only toys the dolphins were making for themselves: some of the creations
were as large as a basketball rim. And Tinkerbell proved able to create
a silver helix, spiraling perhaps 20 feet long, that would spring into
life in a fraction of a second and remain stable in the water as she
swam past, observing it with sonar and vision. then--presto! she would
grab a small silver ring from the helix to play with, while the rest of
the helix degraded into bubbles which would belatedly "remember"
to rise to the surface. This was a wonderful mystery to ponder. My
attempts at re-creating the rings in a swimming pool succeeded only in
getting water up my nose, but my guesses were confirmed--with better and
more rigorous explanation--by the fluid dynamics class of Suchi's close
friend Hans Ramm at Scripps Institute of Oceanography. The silver rings, as it turns out, are "air-core
vortex rings", and the helices are a similar phenomenon. Invisible,
spinning vortices in the water are generated from the tip of a dolphin's
dorsal fin when it is moving rapidly and turning. According to Hans:
"Being unstable without a boundary nearby, the vortex line tends to
form into a more stable form such as a helix. When the dolphins break
the line, the ends are drawn together into closed rings. Owing to the
Bernoulli effect, 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 long period--on the order of 10
seconds. There also seems to be a separate mechanism for producing small
rings, which a dolphin can accomplish by a quick flip of its head.
Creation of these rings by dolphins isn't new.
(far from it--dolphins were probably blowing magnificent silver rings
while our anscestors were hanging off tree limbs). It does seem to be a
relatively rare behavior, though: it has been seen before only in a
specific group of dolphins documented by Diana Reiss and Jan Ostman at
Marine World. "The fact that ring-blowing is rare and that we have
two babies doing it suggests that one baby learned it from the other",
comments Ken Marten. "Whether it was a case of observational
learning, or one "taught" the other, we don't know... but it'd
sure be interesting to know." The social situation also seems to affect
ring-blowing: " The babies made them most intensely when they were
the only two dolphins in the tank and when there was only one adult. The
behavior stopped entirely when they were outnumbered by adults, "
observed Suchi. "During one intense session with Tinkerbell there
were often two or three rings visible in the tank at one time. She
frequently swam over to me in an excited state, then went and made some
more." The reaction to our documentation of these rings
has been universal--people are fascinated by them. Dr. Ken Norris, the
world's leading expert on dolphins, had never seen it before. Robert
Wolff of Apple Computer's Advanced Design Group made a "quicktime"
movie of ring-blowing for display on Mac computers. Arthur C. Clarke,
Earthtrust Advisory Board member, thought they were wonderful--but
debated my offered contention that they might be the first "extraterrestrial
art", pointing to interesting "artistic" achievements by
other nonhuman animals. For myself, I do consider these rings to be "art": the creation and observation of artifacts by a nonhuman mind, with no use other than entertainment and aesthetics. One must be constantly wary not to anthropomorphize the actions of other species--to treat them as though they were human. But after watching a dolphin create one of these kinetic sculptures--observe it from many angles--and then destroy it with a bite--it seems a long leap of logic to ascribe any other motive. This can, and will, be debated... but the beauty
of the rings is beyond debate. As evidence mounts for "self
awareness" and other "intelligent" qualities in dolphins,
I think that it must cause us again to ask the question: what are these
creatures, that they spin silver lariats for the sheer joy of creation?
And what sort of creatures are we, if we cannot appreciate and protect
them? Earthtrust
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There is little doubt that this is what is
occurring. However, understanding the physics should not diminish our
appreciation of this spontaneous act of creation by a dolphin mind.
These young dolphins have detected, understood, and manipulated a subtle
aspect of their environment, for no reason other than play.