Mystery of the Silver Rings
by Don White, Creator of Project Delphis
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.
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.
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 describe
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?
