When we
humans swim, most of us cover distance by using our feet, legs, hands, and arms
as paddles. We push the water back, and move our bodies forward. It is awkward
work for many of us who live predominately in the air and not in the sea.
Sometimes,
I like to think about how dolphins and fish swim. Especially, I’m curious about
how whales cover a thousand miles or more in migrations. The fluke, a whale’s
tail, is a paddle but there is more than the rhythmic motion of the tail and
spine that propels the gigantic mammals forward. I don’t have the opportunity
to watch in person, but I wonder if like the sparrows who seem to shoot up into
the air with little wing activity, the whales don’t have some ability to thrust
forward without paddling. Fish in aquariums move with their tails and flexing
their spines when traveling slowly. But when startled, they dart for cover in a
burst of energy that seems less reliant on the limbs. It’s like a switch from a
propeller plane to a jet plane, or chuting within a fast current. It could just
be one hard thrust of the tail provides the momentum. There could be some other
process for which I don’t have a label, but experts who study life in the
oceans do.
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