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Re: Animal speeds



Thomas R. Holtz, Jr. wrote:
> 
> At 07:32 AM 9/29/97 +1000, you wrote:
> >There has been much controversy over the top speeds of
> >animals over the years. No-one can seem to agree on just how fast
> >a cheetah is, and although more recent attempts claim to have a
> >definitive answer, well, we've heard that before.
> 
> No, we haven't.
> 
> Previous "maximum speeds" are extrapolations in the field from speedometers.
> Almost no variables were controlled.  They were little better than guesses.
> 
> The study in question were timed studies on a course of known length.
> Variables were controlled.  These numbers represent real data.

They're real data, but I have to wonder how reliable they are.  A
cheetah chasing a fake rabbit on a track may behave quite differently
from one chasing a Thommy on open savannah; the track speeds may be
reliable and consistent, but we really don't know how they correlate to
the animal's performance in the field.  For example, sports figures make
a big deal about the terrain they play on; astroturf versus grass in
baseball, clay versus stone versus grass versus whatever else courts in
tennis, and so on.  The terrain the cheetah's running over might make a
big difference in its overall performance.  Further, the range of speeds
between individuals might vary considerably.  The typical range we hear
about is around 65-72 mph; it wouldn't be surprising in the least to
find perfectly capable cheetahs making only 62 mph or so, and it also
wouldn't be surprising to find a Michael Jordon of cheetahs able to make
75-78 mph.  This means a top speed will always be suspect, because we
have to ask "top speed for whom, exactly?"
 
> Granted, they might have had a slow cheetah, or it had an off day, or such,
> but it is a much, MUCH more reliable figure than those published in field 
> books.

Absolutely right.  In terms of methodology the track figures are much
more reliable.
 
> The same goes for elephant speed data: the classic field values are not
> tested, and are suspect.

This is true; however, I'm not sure track figures are the way to go.  My
vote would be for more systematic and reliable field techniques; we've
heard about someone (Alexander?) using film to measure elephant speeds;
this strikes me as a very reliable method if it works out.  Has anyone
else used this method?

Chris