Watching the penguins exit the icy waters in gravity-
defying leaps was the most intriguing aspect of the
assignment. Air is 800 times less dense than water, and
I wanted to understand how these large birds achieve
sufficient underwater speed to overcome the influence of
gravity and leap clear out of the water and onto the ice.
Fully aware that I might have the opportunity to
document a leopard seal attack, I had no choice but to
get into my drysuit and slip into the icy water through
a hole in the thinning sea ice. In this small hole,
barely larger than an average hotel room, hundreds of
penguins raced, executed sharp turns, splashed on the
surface and morphed from the awkward lumbering
mass we have come to recognize on the surface into
one of elegance, grace, power and speed in the frigid,
crystal-clear water of the Ross Sea. I quickly understood
why it is almost impossible for a leopard seal to outrun
or outmaneuver an emperor penguin in open water.
During my first immersion I swam toward a group
of penguins that were busy bathing and preening
themselves on the surface, and I immediately became
completely disoriented by a world of confusion and
bubbles. In a flash, and before I could comprehend
what was happening, all the penguins, who had never
seen a human in the water, had darted into the depths
of the ocean and left me floating alone in the midst
of a sea of bubbles — a “smoke screen” so effective I
could barely see my own hands.
Being naturally curious and very intelligent, the
penguins quickly realized that I posed no danger to them.
To my delight, they soon relaxed and allowed me to
remain in the ice hole with them while they went about
their seemingly endless back-and-forth in the water.
Over the next few days I observed how penguins
use bubbles not just as smoke screens but also as
powerful means of propulsion. I was mesmerized by
the beautiful bubble trails penguins created as they
emerged from the depths of the ocean, where they
can dive down to 1,700 feet for as long 15 minutes.
I couldn’t tell at first if the bubbles came from their
lungs or from their feathers. This physiological
adaptation, known as “air lubrication,” was only
recently described by Professor John Davenport of the
University College Cork and his colleagues in a study
published in the Marine Ecology Process Series.
Watching and analyzing the film Blue Planet, the
researchers discovered that, when on the surface,
penguins raise their feathers to fill their plumage with
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Emperor penguins use a coat of tiny air bubbles on the outer surface
of their feathers to reduce drag and increase their speed as they
rocket to the surface in an attempt to avoid leopard seals.
Opposite: Leopard seals are the apex predators of the Antarctic.
