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RE: Built Like a Race Horse, Slow as an Elephant?

Thanks for clearing some things up for me, being that I am someone who is not a professional in any of these fields, I greatly appreciate the information. BTW, the comparison to a race horse was not a serious one, it was just to emphasize the point that they seem obviously (to me) adapted for running and it was also a reference to Greg Paul's anatomical comparisons in ''Predatory Dinosaurs of The World" But the point of my post is that I think your findings make a great deal of sense, and that the apparent adaptations for running in adults my be a vestige from their youth. Maybe I'm wrong, but the limb proportions of juvenile tyrannosaurs seem to suggest this to some degree. Also, it's hard not to notice that tyrannosaurs seem to at least "look" faster than elephants, so the higher end estimate of 25mph seems to make more sense, but like you said, without hard data this is just an opinion.

btw, thanks for the all the hard work

Simeon Koning

From: John Hutchinson <jrhutch@rvc.ac.uk>
Reply-To: jrhutch@rvc.ac.uk
To: dinosaur@usc.edu
Subject: RE: Built Like a Race Horse, Slow as an Elephant?
Date: Sat, 13 Jan 2007 10:12:55 +0000

Much of this has been covered earlier on the list or elsewhere/in
publications, without much new lately, so my quick response is:

1. Yes, African elephants probably move at the same top speed of ~15mph.
This is published recently by my team in J Exper Biol (pdf available at my
pubs page:
http://www.rvc.ac.uk/AboutUs/Staff/jhutchinson/Publications.cfm  )

2. To me as an anatomist (and someone who knows a bit about racehorses
firsthand), a tyrannosaur is built like a racehorse about as much as it's
built like an elephant. These sorts of comparisons don't help much, in my
opinion.  The locomotor mechanics are fairly far removed from the anatomy.

3. It has been shown that elastic similarity does not apply to tyrannosaurs;
that was a misconception. See papers by Gatesy, Carrano, and Christiansen.
Like most dinosaurs, the interspecific scaling is around geometric
similarity, on average, with a slight but not very impressive positive
allometry at larger sizes. Finally, elastic similarity is a pretty dead
theory for locomotor design; the mechanical grounds it was based upon are
falsified by real data for moving animals (e.g. see papers by Alexander
discussing this stuff). What does exist is geometric similarity (or less
than that, in some taxa) and various degrees of positive allometry, up to
static stress similarity scaling (in a select few species such as
ceratomorphs). Not much surprising or interesting left to say there;
skeletal scaling has been done to death, for the most part.

4. Yes, my work suggests a top speed 15-25mph for big tyrannosaurs. We're
trying to narrow it down but it's challenging considering the many unknowns;
with any method (even good footprints) there is huge potential error so
distinguishing 15 from 25mph is Really Hard.

5. Emu top speeds aren't really documented (same for ostriches); a lot of
guessing though, as usual for animal speeds. Probably somewhere in the
20-35mph range.  People I work with, as well as myself, are trying to add
hard data for this sort of stuff, to end speculations.


John R. Hutchinson
Structure & Motion Lab
Royal Veterinary College, Univ. London
Hawkshead Lane, Herts AL9 7TA, UK
phone  (+44) (0)1707-666-313
fax    (+44) (0)1707-666-371 or 652-090
mobile (+44) (0)7843-629-162
web    http://www.rvc.ac.uk/sml  and

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