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A few comments about dinosaur footprints...
It would be nearly impossible to figure out an animal's top speed by their
fossilized footprints. Maybe you could figure out a thing or two about the
animal's stride, and how many MPH their casual walk was, but NEVER the top
speed. A very good point was raised in THE COMPLETE T. REX, a 1993 book by
Horner and Lessem.
Horner said that footprints are not good evidence for determining top speeds
of dinosaurs. The ground needed to be SOFT in order for the footprints to be
preserved. Now what dinosaur in her right mind would run top speed in
slippery mud? No Tyrannosaurus or Utahraptor I know of. In all of the
footprints of dinos. preserved, the creatures that made them were probably
walking slower and more carefully than they usually do. (Well, most
sauropods are plain walkers to begin with.) A theropod, for example,
wouldn't risk running after its prey in ground like that -- sometimes one
fall can be deadly for a horizontally-bipedal animal. And even the large
quadrupeds probably didn't risk it either.
So, since most dinosaur footprints preserved show no indications of top
speed, does that mean we have to simply speculate? Maybe, maybe not. Are
they any good ways of determining an animal's top speed from its weight and
limb structure? Maybe a little model with the proper skeletal and muscular
structure could show how far the limbs would swing forward in both running
and walking strides. Exactly HOW do dinosaurs run, anyway?
It's obvious that the theropods walked like overgrown ratites (in some cases,
undergrown). As Bakker puts it, T. rex is the 6-ton roadrunner from hell. A
little big of an exaggeration, but true enough. T. rex may have ran down its
prey, and used its big chompers to tear out yard-deep wounds, or with the
small frys, simply shake them to death (like the T. rex killing the
Gallimimus in Jurassic Park). T. rex didn't have the most avian run of all
-- Ornithomimids and the other 'protobirds' (Paul's term for late birdy
theropods) probably looked a lot like birds when they ran.
Dromaeosaurs probably weren't really speedy hunters. I have heard that a
shorter femur lets you go faster, since a shorter femur lets the back legs
swing more, I suppose. Dromaeosaurs definitely couldn't run cheetah-speed --
besides, cheetahs are quadrupeds, and their stride is a lot different from
theropods'. Dromaeosaur legs are really quite short compared to, say,
Ornithomimus, with a rather long femur. And since Ornithomimus has been
calculated to run at about 40 mph (or a little more), dromaeosaurs like
Deinonychus were probably slower. But, if a pack of dromaeosaurs ambushed
their prey, they could run it down quickly, pin it to the ground, and issue
the coup de grace without running that much (a pack of Deinonychae would be
slightly overwhelming to a single Tenontosaurus).
So, while dinosaur footprints cannot be exclusively used for determining top
speed, they may give some indications of dinosaur behavior and movement.
Such as the sauropod herds with the youngsters in the middle, the allosaur
pack stalking the sauropods, a carnivore attacking small ornithopods, the
carnivore/sauropod chase, and the swimming dilophosaur and apatosaur. So we
can learn about dinosaur social structure, attacking methods (be careful not
to slip!), and even how dinosaurs swam (whenever they did). Could the
deepness of dinosaur tracks give an indications of dinosaur weight?
Comments and corrections are welcome.
Raptor RKC (Rachel Clark)
A human physically but a raptor at
Teen residing in New Joy-zee.
Studies dinosaurs and nature, loves animals (especially guinea pigs)
"Look at people for what they are, not for what they aren't."