Let me re-phrase the question. Yes,
trackways provide 'estimates' or 'inferences' rather than
But I have seen inferences on dinosaur speeds made
from the relative proportions of the limb bones. (And opposite conclusions
made when discussing the limbs of a rather famous large theropod). I have
also seen physics-based calculations used to infer speed limits based on ability
to survive a crash.
It seems to me that trackways, combined with
physics-based calculations (that to me seem just as well-founded as the above),
represent a step up in degree of confidence in the inferences one is able to
draw. After all, a track does provide a record a living animal;
and calibration of the calculations against living animals provides another
Finally, it seems that a theropod as large as
Acrocanthosaurus running at a calculated 36 km/hr should have some relevance to
the question of how fast the large guys could run. Trackways showing
evidence of running are rare, not unexpectedly. I am only aware of these
2. I was just wondering if there were others, and when the same
calculations are used, give similar or higher values. I will
add a further question: what are the plus/minus values attached to these
equations? Even if the answer is a factor of 2, as shown in a figure from
Bakker in Dinosaurs Past & Present Vol 1(1987), would not this still be
----- Original Message -----
Sent: Thursday, February 14, 2002 1:53
Subject: footprint fallacies (was "Large
theropod speed record")
Reading the recent
news on the new dinosaur tracks in the UK got me wondering. What is
the current trackway evidence for large theropods?
er....there IS trackway evidence of large theropods :-)
which means they probably walked around, at least some of the time. (At
least, trackways indicate that large theropods didn't all fly, or swing from
treetop to treetop...)
I am aware of
only two trackways of running large theropods, this recent British study
quotes 30 km/hour and Kuban, 1989, quotes 36 km/hr for a trackway in Glen
Right. And as we all know,
speed = distance/time.
And of course, we know exactly how long it took for the dinosaur in
question to cover the ground and make that trackway....
oh wait, no we don't. Darn, can someone invent time travel please?
Please please please - while dino tracks are really cool, and give us
lots of interesting info, we can NOT - and never will be able to - tell
the ACTUAL speed at which they were moving when they left a particular
trackway. The figures given in various articles should be taken with a liberal
sprinkling of salt. At best, we can estimate the "relative" speed - and say
something along the lines of 'dino A was moving twice as fast as dino B'. But
even then, you can only compare two critters of the same size and taxon.