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Re: Troodon feeding habits
Greg Paul wrote (8/6/96; 11:44a):
>According to my models, the slender tail of a troodont would make up
>about 5% of total mass.
The tail of Troodon is clearly very slender, and 5% certainly looks like
a good figure. But, this would mean that reconstructed skeletons (on
paper) and artists renditions of Troodon are out of balance. There isn't
nearly enough mass behind the hip socket (acetabulum) to balance the mass
in front of it. In other words, the center of gravity was forward of the
acetabulum. Presumably, then, the femur of Troodon sloped forward as
well as downward, so the feet were placed directly below the center of
gravity, forward of the acetabulum. I wonder of the toes would stretch
far enough forward to reach a position directly below the center of
gravity, without some help from a forward-sloping femur?
Front-heavy Troodons are illustrated in the July issue of National
Geographic, on p. 83. A front-heavy Troodon skeleton is illustrated
in the David Lambert book on dinosaurs (it's at home & I can't
remember the title--a published by Kindersley/Dorf....? something like
that--_The Complete Dinosaur_, maybe?; never mind [I think he means
_The Ultimate Dinosaur Book_ -- MR]). I think skeletal
reconstructions and artist's renditions are out of balance for a
number of different theropods in various books. I mean ones that are
just standing there, not the action shots where they're poised and
leaning forward as if running.
The caption for the National Geographic figure (July, 1996, p. 83) refers
to a pack of "deadly sand bears" off in the distance. I can't tell what
these "sand bears" are supposed to be, and there is no reference to them
in the text or in other illustrations. The perspective is difficult, but
various visual clues suggest that the "sand bears" are about the size of
a cow. My contention is that animals of that size would indeed be
potentially deadly to Troodon. Does anyone know what these "sand bears"
are supposed to be?
Greg also said:
>...cheetahs are gracile, and they regularly kill ungulates as big as
> themselves. No reason to think troodonts could not do the same.
I had allowed that Troodon might have fought each other, thus were not
endangered by opponents (or prey) of size similar to themselves. Again,
we're having trouble with the words "large" and "small." Tracing the
history of this thread, I guess prey as large as a Troodon would indeed
be large compared to the mammals they also might have preyed upon (as per
the recent "Paleoworld" show). In fact, I agree that Troodon could
probably handle prey up to a few hundred pounds, but I was not thinking
of such prey as being truly "large." Of course "large" doesn't have to
be as large as an adult duckbill or ceratopian, either. Perhaps cow
size! Guess I have to work on specifying reference points for "large"
and "small," since those terms seem to be nearly meaningless without
Norman R. King tel: (812) 464-1794
Department of Geosciences fax: (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712 e-mail: email@example.com