Re: Dinosaur speeds

[Betty Cunningham <bettyc@flyinggoat.com>]

I suspect >young< elephants can trot and pace as I am remembering seing
them do so in one or two Nat Geo and Nova specials,  but this is from
memory and that's not dependable.
Eadweard Muybridge, in ANIMAL LOCOMOTION, refers to the elephant
fast-walk, as an 'amble'

-Betty

NJPharris@aol.com wrote:
> 
> In a message dated 1/26/00 10:18:56 PM Pacific Standard Time,
> knc3@coopresources.net writes:
> 
> > I've seen footage of angry bulls that are moving at much more than a trot.
> 
> Yes, but it's still kind of a hurried walk, without the
> four-feet-off-the-ground phase of running or the up-and-down motion of a
> trot.  For many sauropods, I don't doubt that elephants are decent models
> (though diplodocids, with their short arms, must have looked rather different
> when they walked).
> 
> --Nick P.

   From: John R. Hutchinson" <jrhutch@socrates.berkeley.edu>

>From: NJPharris@aol.com
>To: dinosaur@usc.edu
>Subject: Re: Dinosaur speeds
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>In a message dated 1/21/00 8:16:18 AM Pacific Standard Time,
>jrhutch@socrates.berkeley.edu writes:
>
>> However, I don't trust relative stride length [= stride length/ hip ht] as
>>  a conclusive indicator of gait.  We had elephants walking at a 2.8 RSL
>>  which according to Thulborn should be a trot (trot= 2.0 to 2.9 RSL); it was
>>  not even close.  (we presented this stuff at SICB, and I know others have
>>  recently made similar conclusions)
>
>Elephants don't trot, do they?  Elephant legs are put together rather
>differently from those of theropods (much straighter through the whole step
>cycle, for one thing), and this makes me wary of studies based on elephants
>being extrapolated to theropods.

No, elephants do not appear to trot.  At the fastest speeds recorded
empirically, they are still doing a (very fast) walk.  To a
biomechanist,
"trot" and "walk" have specific meanings and are diagnosed by different
stride parameters.  An animal moving quickly is not necessarily
trotting;
trotting depends on factors such as the relative phase of footfalls,
duty
factor, etc.  Trotting is a "bouncing gait"(as is galloping) in which
there
is potential for elastic strain energy storage in tissues; walking is a
"pendulum-like gait" in which there is little or no ESE storage but
rather
potential and kinetic energy are exchanged.

-- 
Flying Goat Graphics
http://www.flyinggoat.com
(Society of Vertebrate Paleontology member)
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