a little background

[John R Hutchinson <jrhutch@stanford.edu>]

Hi again,

        

Sorry
about the long post previously; I hope people are not responding by
attaching the whole text without cutting+pasting.  Here is another
long post.  Don't worry, I will shut up soon enough. 
:)

        

Some
history behind our research might help people understand where we're
coming from with this study.  If my tone here sounds defensive, it's
because I am grouchy from lack of sleep, overcaffeination, endless
phonecalls, and annoying e-mails from yahoos who tell me that gravity was
much lower in the Mesozoic era, so I am wrong.  [I'm no astronomer
or geophysicist, but as far as I know "g" was still close to
9.81 m/s^2;  only 65 mya...... if anyone knows of published papers
that discuss this I'd love to hear more]  Believe me, the dinolist
is a breath of fresh air compared to the creationists and
pseudoscientists who have now started to flood my mailbox.  I can't
wait to see what the Enquirer does with this... shiver.  Anyway, I
am trying to be honest and forthcoming in this e-mail to dispell any
illusions about our research, which has become overhyped and
misinterpreted despite our best intentions and efforts (shit
happens).

        

I am not
at all ashamed to admit that I was inspired in the 1990s by reading a
copy of Gregory S Paul's book Predatory Dinosaurs of the World.  It
really brought dinosaurs to life for me, and I loved it.  Ditto for
Jurassic Park when I saw it later.  Both experiences convinced me
that I wanted to study dinosaur biomechanics in grad school.  I
think I might have even asked Greg if he was accepting grad
students!  At a biology conference I ran into Bob Full, who studies
cockroach and other animal biomechanics.  I was applying to Berkeley
to work with Padian, and told Bob that I'd love to build some tyrannosaur
models like he and his students did for insects.  He jumped and
said, "We've been looking for a student to do that for
years!"  And so I spent 6 yrs at Cal doing that.  Now Ive
spent almost 7 years on the dinolist, often quite vocal, especially in my
impetuous early days.  I am no stranger to dinosaur
science.

        

Anyway, I
always found Greg and others' arguments about fast tyrannosaurs very
interesting, and at times convincing.  Greg has made the best (by
far) arguments for fast-running tyrannosaurs, ever.  Bakker barely
scratched the surface and I didn't read Dinosaur Heresies until much
later.  No one else has done anything that convinces me; Greg's work
is the only one with much substance to it.  He has published work in
peer-reviewed journals and his opinions deserve respect; he's been very
observant as many professional paleontologists have noted before.  I
mean him no personal insult by disagreeing with him.  This is just
science and I try to keep it that way.  He or someone else might
prove me wrong, and I could live with that.

        

Where
Greg's research and our research disagrees is on the use of anatomy to
estimate locomotor performance.  We both agree that anatomy is
extremely important, and I consider myself to be an anatomist first and
foremost (hence the slew of long papers about it, which led up to this
study, and subsequent papers with Carrano and others soon).  As a
biomechanist, I know that in order to move at a certain speed or execute
any other activity, an animal must exert a certain amount of force, and
that force scales more slowly than body mass does.  That's what led
me to doubt Greg's and others' arguments, and we explain our logic in the
paper quite clearly I hope.  Our website goes into some more detail,
and I encourage people to read up on work by Biewener, Alexander, and
many others.  The methods and evidence we use are standards in the
field and hold up well to experimental analysis.  Given the amount
of unknowns for tyrannosaurs, we still might be wrong, but we have done
our honest best with what the fossil record and living realm
provide.

        

After ~4
yrs in grad school of dissecting animals, studying fossils, and working
on live animals a bit, I felt like I'd learned enough about tyrannosaur
anatomy to do some simple models of tyrannosaur biomechanics.  I
asked Mariano Garcia, a postdoc in Bob's lab, to help me with the
computer stuff, and we were pretty sure we could get a paper out of
it.  Two years later, I finished my thesis and we submitted the
paper to Science.  Rejected without review; "interesting but
too specialized"   (i.e., too much math? or just
boring).  Fine, over to Nature then.  Two anonymous reviewers
who seemed to know their dinosaurs and biomechanics quite well gave
favorable reviews, so it was published after some revisions and added
analyses at Stanford.  Here, I now am learning more biomechanics
skills from people who study humans, and use models to show how humans
work.  The models work for humans, by the way, and frogs and
cockroaches, etc.  Physics transcends the essentialism of taxonomy
as long as the biology is reasonably captured along with the
physics.

        

Now we're
caught up.  I hope people understand that this was not some project
that Mariano and I sketched on a napkin after a few beers last week, and
decided to publish as an assault on paleontology, and then abandon to let
paleontologists pick up the pieces.  This was a lot of work and we
are serious about it, and I will continue pursuing these sorts of
scientific questions for the rest of my career.  I welcome
disagreement with our work as long as it is scientific and not
superficial.  I expect SVP next year will have at least one talk
criticizing our research, and I'm sorry that I won't be there this year
(first time in 6 yrs!) to respond.  We'll work things out in the
scientific peer review process over the next few years, I hope.

        

Back to
work for me.  Take care, everyone.

John

===========================================
John R Hutchinson
NSF Postdoctoral Research Fellow
Biomechanical Engineering Division
Stanford University
Durand 209, BME
Stanford, CA 94305-4038
(650) 736-0804 lab
(415) 871-6437 cell
(650) 725-1587 fax
http://tam.cornell.edu/students/garcia/.trex_www/naturepaper.html
===========================================