TheSell of the SCALY_FOOT SNAIL

It has one of the strongest exoskeletons
ever discovered in nature. The scaly-foot
snail, found at the floor of the Indian Ocean,
can withstand the water pressure occurring
at a depth of some 8,000 feet (2,400 m).
Furthermore, this little mollusk is unaffected
by both the high acidity of the water and its
fluctuating temperature—including the hot
water that gushes forth from hydrothermal
vents. The shell also shields it from attack
by predators.
Consider: The shell of the scaly-foot snail
has three layers. The first is composed of
iron sulfides; the second resembles the protein
coating found on other snail species;
and the third is made up of a calcium mineral
called aragonite. With its triple layer of
defense, the scaly-foot snail is impervious to
attack by predator crabs, which try to crush
the shell with their powerful claws. The crab
may grip the snail for days at a time, but the
shell holds fast.
Using a diamond-tipped device called
an indenter, researchers learned that “the
outer shell is designed to crack in a way that
absorbs energy,” reports Discover magazine.
“Cracks spread only by fanning out around
the iron sulphide particles. This ‘microcracking’
not only absorbs energy, it also ensures
that larger cracks do not form.” Meanwhile,
the middle layer absorbs the mechanical
energy exerted during an attack.
Researchers hope to copy the structure of
the scaly-foot snail’s shell in order to produce
stronger helmets and bulletproof vests,
as well as ship and aircraft hulls. “Even Arctic
oil pipelines that are buffeted by icebergs
could benefit,” says Discover.
What do you think? Did the shell of the
scaly-foot snail come about by chance? Or
was it designed?
(AWAKE June 2011)