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Re: FW: 6th International Congress of Comparative Physiology and Biochemistry (long)

From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>

23.3. Theropod agility?

Contrary to recent media depictions, the agility of theropod dinosaurs
may have been severely limited by the large rotational
inertia of their horizontal trunks and tails. Bodies with mass
distributed far from the axis of rotation have much greater rotational
inertia than bodies with the same mass distributed close to the axis of
rotation. In this study, we increased the rotational inertia
about the vertical axis of human subjects by 9.2-fold, to match our
estimate for theropods the size of humans, and measured the
subjects' ability to turn.

Although the authors of this paper raise some interesting points, I'm left wondering about how much the leg musculature of the dinosaur in question would factor into this? Surely a theropod with legs the size of tree trunks would be better able to carry its weight through a turn in comparison to us puny humans.
I don't doubt the author's point re: rotational inertia... I just question the degree to which they figure it plays an importance. :\
Any thoughts?

Jordan Mallon

Undergraduate Student, Carleton University
Vertebrate Paleontology & Paleoecology

Website: http://www.geocities.com/paleoportfolio/
AIM: jslice mallon

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