Stories for Thinking Children-2

pressure that may take place or ripple
in the water, or the smallest distur-
bance in its flow, right away be-
cause of special sensors on our
lateral line. By sensing vibrations
we know when an enemy or an
obstacle is present without actu-
ally seeing it with our eyes. These
detectors are particularly sensitive
to nearby low frequency vibrations.
For example we can perceive foot-
steps on the shore or anything thrown
into the water right away, and behave ac-
cordingly."
Omar nodded enthusiastically: "Now I understand. I can sing or
play the radio out of the water and it doesn't make you uncom-
fortable, but at the slightest vibration I make in the water, for ex-
ample if I shake the jetty or throw a stone into the water, you all
disappear!"
His new friend went on: "Omar, this system of ours, which sci-
entists call the fish lateral line, is really a very complex structure. It
is not possible for such a system to have developed by chance or