Travel Reference
In-Depth Information
Our kinship with the many-talented mollusks
What talented and successful creatures the mollusks are! We are privileged
to share the planet with them, and in some modest way to claim kinship with
them.
The mollusks have survived by a wide variety of methods. The clams, the
mussels, and their numerous relatives protect themselves from predation with
strong shells. The cuttlefi sh and octopuses use jet propulsion to escape from
predators. Many of the most highly mobile mollusks lay down decoys of ink
clouds and escape in the resulting confusion. Various mollusks have evolved
the widest variety of eyes found anywhere in the animal kingdom, eyes that can
perceive dangers in their environment in many dif erent ways. Because of their
sophisticated eyes, cuttlefi sh and squid can use elaborate color and luminescence
patterns to attract the opposite sex and warn against predators. And, as we have
seen, the octopuses and cuttlefi sh are masters of disguise, using information
gathered by their eyes to cleverly match their bodies to their environment.
We chordates, diverse as we are, are boringly predictable compared
with the mollusks. Although it is true that vertebrate chameleon lizards can
change color, we backboned animals are embarrassingly untalented in other
ways. None of us can produce and retract colorful bumps all over our bodies
within seconds, like a cuttlefi sh can (goosebumps don't count).
The most astonishing mollusks of all, the octopuses, have simultane-
ously evolved high intelligence, the most detailed and complex methods of
disguise in the animal kingdom, and the ability to emulate Plastic Man and
squeeze through impossible places. It is true that vertebrate snakes can fi t
through small holes, but they already have a small cross-section. A soft-bod-
ied octopus can squeeze through any hole that is larger than the tiny soft car-
tilaginous “skull” that lies buried deep within its massive but highly deform-
able head. A two-foot octopus can squeeze through a one-inch hole!
The dif erences between ourselves and the mollusks, immense though
they seem to be, are beginning to close. Because of convergent evolution our
eyes are remarkably similar. And so, in some respects, are our behaviors.
Octopuses are the only non-vertebrate animals known to be playful, having
