Hi Tweets

One notion to be entertained concerning the unison swimming of the captive
penguins is that the birds are exhibiting highly stressed stereo-typical
behaviors. Sustained rapid swimming does not suggest foraging behavior or
"exercise swimming". The introduction of non-aclimated birds into a novel
environment may have triggered the flight response of these new arrivals.
The flight response is one of the strongest social contagions that animals
possess. I doubt if the resident penguins "had to be convinced", but
probably joined on their own accord as they became alarmed by the behavior
of the new recruits.

In the wild the birds would probably increase their distance from a
perceived threat, or find a predator free refuge and calm down. Predator
avoidance is essential up to a point, but must traded off with other
behaviors (plumage maintenance, foraging, etc.).

I have had the good fortune to have conducted studies on predator avoidance
on schooling fishes in a laboratory environment. Sometimes it was possible
to extinguish the fishes flight response by modifying a few environmental
variables such as light levels, water velocity, or by providing escape
habitat (where the individuals can feel secure). In fact, it has been shown
in krill schools that by simply removing contrasting visual stimuli (i.e., a
grate on the floor of the tank or covering an overhead radiator) it will
stop frenzied avoidence behavior. In the wild, a contrasting dark object
(in their normally uniform visual field) is perceived an approaching
predator.

On the other hand, maybe the penguins have some unusual pre-breeding
aggregation response similar to murres. A possible test of this "100th
penguin syndrome" would be to examine for reproductive hormones VS stress
hormones.

Fred Sharpe
Sequim Bay Point


SAN FRANCISCO - A few penguins swimming leisurely every now and
then at the San Francisco Zoo is nothing new. But dozens of them
doing laps in unison all day to the point of exhaustion has
zookeepers perplexed.

"We've lost complete control," said Jane Tollini, the zoos penguin
keeper. "It's a free-for-all in here. After 18 years of doing this
job, these birds are making mincemeat of me."

It all started in November when six newcomer Megellannic penguins,
formerly of Sea World in Aurora, Ohio, were brought in.

Since then the penguin pool at the San Francisco Zoo has been a daily
frenzy of circle swimming by all of the 52 birds at once.

The penguins start swimming in circles early in the day and rarely
stop until they stagger out of the pool dead tired at dusk.

The six penguins from Ohio started it all, Tollini said, apparently
convincing the others to join them for the watery daily circuit.

"I can't figure out how the Aurora penguins communicated and changed
the minds of the other 46," Tollini said.

On a recent day, Tollini said that the penguins would normally be in
their burrows in pairs. Instead they swam dizzying circles at her feet.

She hand feeds them all, names them, and monitors the penguin enclosure
that has become a bit of a lap pool. The pairs, Pearl and Bluto, Grumpy
and Shamu, Captain and Ditz, all have taken part in the bizarre circle
swims.

Some penguin experts point to the highly social animals as being open
to new ideas fostered by newcomers in to the zoo's so-called Penguin
Island.

"Penguins are extraordinarily social birds," said Christina Slager,
associate curator at Monterey Bay Aquarium. She has studied Magellanics
in the wild in Patagonia and Chile.

"And they're very, very inquisitive. If you combine those facts and
put in a new stimulus, like the six new penguins, they have to check
it out."

Ian Hiler, director of touring exhibits at Audubon Aquarium of the
Americas in New Orleans, said it only takes a couple of headstrong
penguins to start a trend - in this case a seemingly endless exercise
in swimming.

"Usually there are one or two dominant birds," Hiler said. "Somehow
these animals came up and showed they're worthy of being followed."

Aquatic biologist Pam Schaller of the Steinhart Aquarium in San
Francisco described it in more matter-of-fact terms.

"Genetically, they're designed to swim," Schaller said. "I'd be more
amazed if the six had learned to do something not in penguin nature
and showed the other 46 how to do it - like if the birds were trained
to jump through a hoop."

Tollini said genetics aside, she hopes the Mark Spitz routine stops
soon.