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Re: T. rex & predatory behavior (was: Jurassic Park 4: Electric Boogaloo)

1.) On Monday, February 07, 2005 12:05 AM
"Jordan Mallon" <jordan.mallon@gmail.com> wrote:

> You don't have to look as far as the Carcharodontosauridae to see
> packing behaviour in theropods if you consider Barnum Brown's original
> Albertosaurus bonebed in Dry Island, AB as evidence of gregariousness.

Yes. Thanks. In the discusion of the predatory/scavenging behavior
in T. rex I first taught of that TV programme because they mentioned
the animal in it.

2.) On the
started here on the list.

Here's something on predatory behavior of T. rex:

James O. Farlow and Thomas R. Holtz, JR. 2002.
Paleontological Society Papers, v.8:251-266.

"Predation vs. scavenging.âPerhaps the best
known predatory dinosaur, Tyrannosaurus, has
been suggested to have been an obligate scavenger
(Horner, 1994; Horner and Lessem, 1993; Horner
and Dobb, 1997). Horner (1994) argues that several
morphological features of Tyrannosaurus would
have precluded a predatory lifestyle: 1) relatively
small size of the eye that would have prohibited
spotting prey at a distance; 2) limb proportions
indicative of slow top running speeds, which would
have prevented Tyrannosaurus from chasing and
capturing prey; 3) disproportionately tiny forelimbs
that would have been useless for holding prey; 4)
relatively broad teeth that depart from the expected
blade-like configuration for teeth of a predator.
We do not find these arguments persuasive. The
size of the orbit of Tyrannosaurus relative to its skull
size is in fact rather large for a reptile of its size
(Fig. 3). Furthermore, the dimensions of the orbit
suggest that Tyrannosaurus had a big eye in absolute
terms, which would have increased its lightgathering
capacity and thus its acuity (Walls, 1942;
Dusenberry, 1992)."


"...metatarsus/femur or tibia/femur length ratios
indicate that it was likely as fleet, or faster, than
other big theropods, and certainly faster than the
herbivorous dinosaurs that were its likely prey
(Gatesy, 1991; Holtz, 1995).

Hornerâs last two arguments strike us as begging
the question. Without explicitly saying so, he is
hypothesizing that grasping forelimbs are a necessity
for killing prey (which will be news to wolves,
seriemas, and secretary birds), and that animals with
broad-based teeth are unable to kill prey with them
(which orcas and crocodiles will find surprising).
Because the morphology of Tyrannosaurus matches
the predictions of his hypotheses, Horner concludes
that Tyrannosaurus could not have been a predator,
without first testing those hypotheses.

The brain of Tyrannosaurus had respectably
large olfactory bulbs (Brochu, 2000), suggesting
that the sense of smell was quite acute in this
...a keen
sense of smell would have been useful for picking
up the scent of live prey"


"In short,
we suspect that Tyrannosaurus and other
carnivorous theropods were, like most extant
predators, opportunistic carnivores, eagerly
searching for carrion (in which activity the large
body sizes of many theropods may have been an
advantage; Farlow, 1994), but also killing prey
whenever possible."