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RE: thanks for tracks & a question
From: RAY D STANFORD [SMTP:STARSONG@prodigy.net]
Sent: Saturday, February 27, 1999 1:26 PM
To: Stewart, Dwight; firstname.lastname@example.org; Dino mailing list
Subject: Re: thanks for tracks & a question
Hello Dwight, Jack, and List,
It has been several days, Dwight, since you asked another good
about what might be determined from study of dinosaur trackways.
those who may have forgotten the question, I'll repeat it:
"Okay, this brought a question to mind that was rattling around
my head a few weeks ago. To whit: can anything
be inferred about dinosaur mass/weight from the prints, aside from
the "wide/narrow" gauge artifact you just mentioned?
Here, I was thinking of forensic work as the model, in that the
approx. height & weight of a human can be derived from
shoe size, stride length, & the depth of the tracks. Now, I realize
that preservation conditions would greatly complicate
this, as would the question of under track, over track, etc. But,
nevertheless, it seems intuitively feasible."
Yes, forensic work does provide a good model of ways to derive a
amount of data especially from trackways, but even from singular
some instances. Of course, as you mention, the derivations will be
accurate when one is working from prime tracks, rather than
A good reference on matters related to this is a small but very
little book entitled, DYNAMICS OF DINOSAURS & OTHER EXTINCT GIANTS
McNeill Alexander, and published by Columbia University Press in
Yes, 'ball-park figures' for an animal's velocity (or lack of
it) can be
derived from trackway (or track) studies. Of course, trackways are
this, but singular tracks can reveal certain limited data. In the
case, for example, I have found several Theropod tracks (various
sizes) in which an animal was making a very fast change of
can easily determine by observation, the degree to which the foot
(relative to the horizontal layering of the sedimentary substrate)
the turn, the amount of substrate that is pushed up by the
involved at the moment of turn. Then, from these observations and
data (and calculations) one can come up with reasonably reliable
substrate penetrability and compactibility at the time of the event,
animal's approximate mass, and probable velocity, etc.
Two of the things that have surprised me about some of the
from Maryland's Early Cretaceous is that apparent speed and
there are the several tracks possibly made by Dromeosaurs with that
second-digit's 'terrible claw'! I had never thought about the tip
claw being so knife-blade thin and awesomely sharp (probably because
been thinking mainly in terms of the claw bones we see, instead of
longer, sharper keratinous sheath that surrounded it in life), but a
of the tracks I've found here leave no doubt in my mind that this
Theropod was truly a 'Jack the Ripper'.
Thanks, Ray. I figured that HAD to be the case. The track evidence
& maneuverability certainly seems to imply active hunting behavior.
there tracks from more than one Dromeosaur at the same site? What
at here is evidence of pack hunting.
There are a few tracks with substantial amounts of 'splash-out'
suggesting a surprisingly high-speed run in very wet soil that was
all the same -- covered with water (or the splash drops would not
Those conditions would logically dictate lower than maximum speeds,
which at least
leaves open the theoretical possibility of much faster speeds on
more solid ground,
I hope this provides some insight, and I shall forgo quoting any
formulae Alexander provides in the book mentioned (or any of the
available in various publications).
Some work has already been done to extrapolate quantitative data
trackways, but it seems to me that this is a fairly new field of
with much more potential than what has yet been realized, especially
uses sophisticated computer software designed for modeling the
its effects. I'm not as yet aware of any off-the-shelf software
designed for this kind of work, but I suspect there are some extant
software that could help in (or be modified for) this type
One area in which I use computer technology to study tracks (and
few small trackways available to me) is via IMAGE PROCESSING.
sometimes reveals meaningful details that had not been noticed
also has enabled less-experienced observers to readily perceive
and hence to interpret the tracks with more insight. So far as I
know, I am
the first track researcher to utilize this helpful innovation in
Relevant to this: Several summers past, I had time to do some
tracking in Texas, where I found something so surprising and
exciting that I
slept very little for a couple of weeks after the discovery : The
short trackway of a
HATCHLING Sauropod from the Comanchean (Lower Cretaceous) of Travis
consisting of three clear imprints and a fourth (right manus) that
clear and possibly distorted by the right pes (back foot) coming
close behind that right front foot. In other words, there are two
(shallow but beautifully detailed) left and right pes (back foot)
and one equally superb, right-manus imprint, along with the
much-less clear right
manus (front foot) impression.
AH, Travis County; where my son lives; about 75 miles north of us.
My understanding is
that the Mesozoic fossil record is better in Travis than Bexar
County (where I live).
Since it was from the Comanchean, was this sauropod a Titanosaur?
Dimensions? Well, each of the two pes impressions is only 5.8
length, while the manus measures only 3.0 cm in width! These
little tracks are recorded in a carbonate (marine lagoon) substrate,
and are the
first hatchling sauropod tracks documented anywhere. If we take the
Paluxy Sauropod pes length to be 85 cm long, then at 5.8 cm, the
county hatchling pes is only 1/14.6th of that size!
Image enhancement of a photo of this track-bearing slab made the
Sauropod tracks show up ever more marvelously, revealing some
details that had
not been noticed before enhancement.
Those tiny Sauropod tracks are virtually identical in form (but
size, of course) to the best of the Paluxy river-bed tracks of
that the four sharp claw marks on each pes imprint (the 5th toe
represented only by a bulge of the foot flesh positioned
to toe 4) seem to have been made by claws even shaper and,
longer than corresponding claws in imprints made by the more-adult
sauropods. Dr. Robert Weems of the U.S. Geological Survey, Reston,
Virginia, has speculated that long, sharp claws on the hatchling
may have been useful in escaping from the egg shell when hatching
and that the claw sharpness probably diminished as the hatchling
and more in silt, sand, or across pebbles, thus the sharpness of
suggest that this particular track maker was very recently hatched.
Some skeptics out there who have not had the chance to see these
might wonder whether, knowing the shapes of the Larger Texas
tracks, some of us might have just imagined that random forms in the
carbonate substrate look like the Paluxy Sauropod tracks. Well,
would take care of that; but since I cannot include illustrations or
in postings to this list, I shall mention one other nice advantage
computerized image processing: Using absolutely none of the artwork
capabilities of the computer, but using a series of commands that
computational, only, I had my system look for and draw the outlines
whatever forms it detected on the slab. Really, to my astonishment,
ever far better outlines of the Paluxy-like hatchling tracks than I
imagined (in my wildest hopes) it would do! My point? My computer
fantasizing Brontopodus birdi type tracks, as a sight-unseen skeptic
speculate those of us here had done.
Excellent images of many of the small to medium-sized tracks can
obtained by simply scanning them on my flat-bed scanner, which has a
surprising depth of field. This provides a quick and easy way of
the collection with high quality color photos that include
That's it for now.
Again, thanks Ray.