>>>I think Wally has a good suggestion as well, although I think that would
just be a side effect/benefit/selection and not a root cause for swallowing
the sand... "ballast" <<<
Its been many years since I read the paper, but I believe Bill Matthews also
suggested that as a possibility.
>>>I bumped the current
waaaaaaaaaay up in-in-least the 30 long. I have become incredibly enamoured
(was that obsessed?) with "the physics of the biology"....The hogsucker is a
great example, as the head acts like a forward facing
keel . They arch their backs and use their tail to keep that head down,
which allows them to effortlessly move about where they want in the
current.<<<
We see similar behavior in other riverine fishes. Sturgeon, especially, can
maintain station in fast flows by sitting on the bottom, arching their
backs, pushing their nose down, and turning their fins up and back. We
originally called this behavior "hunkering" but an editor suggested that
that was poor terminology (not translatable into foreign languages and
possibly colloquial) so the term was changed to "substrate appression."
For a physics-based interpretation of swimming, check out Steven Vogel's
"Life in Moving Fluids." Book was available in Edward R. Hamilton for just
a few dollars.
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