Re: Horner on NBC Nightly News

["Demetrios M. Vital" <vita0015@umn.edu>]

On 18 Jul 2001, Chris Collinson wrote:
> I really can't understand why Horner is so stubborn not to believe T-rex
was
> a predator. The leg proportions are exactly that of a scaled up
> ornithomisaur, so it could run quite fast.

As was mentioned, it may have broken bones if it had an aerial phase.
While, yes, T. rex bones are like scaled up ornithomimosaur bones, to
paraphrase Matt Carrano, they're both extinct, so we don't really know what
stresses they could deal with.

> It had the biomechanics of a bird
> not an elephant and so had pneaumatitized bone making the beast much
lighter
> and nimbler, than would be expected for such a large animal.

But if it had no aerial phase, as recently suggested by John Hutchinson and
Matthew Carrano, then it moved more like an elephant, another animal with
no aerial phase.  Heck, Hutchinson recently speculated that T. rex couldn't
move faster than 9 mph!  Matthew Carrano gave me fifteen or twenty mph top
speed for T. rex and eight to twelve mph for Anatotitan in a personal
correspondence.

> Due to its
> nimbleness it could likely take a fall with the best of them!

Which are what?  No other large species to compete with, besides itself,
and it definitely hunted both Triceratops (which couldn't gallop) and
Edmontosaurus (which couldn't move faster than T. rex).  So whether they're
the best or not, it obviously preyed upon them.

And, I believe, it was James Farlowe who did a study saying that T. rex
would die if it fell moving above thirty miles per hour.  Since it couldn't
move that fast, I don't know what would happen if it fell.

But, there are some things to take into account:  I have never seen an emu
or ostrich fall (on TV).  I've seen them run into fences, I've seen Steve
irwin wrapped around their legs, I've seen nature shows up the Wazoo, but
never a modern bipedal cursor fall.  The second thing to take into account
is that elephants can't stay laying down for long periods of time because
their own weight will cause the tissue to become necrotic.  But, then
again, T. rex had to be able to sleep laying down, unlike elephants; I
don't think it could stay standing on two legs all the time.  What to make
of all these unscientific observations, I don't know...yet.

> The only
> arguably valid point that Horner makes is T-rex's specialized bone
crushing
> jaws, analogous to modern day scavengers the hyenas. However, hyenas have

> Leopards, Lions, Cheetahs, Cape dogs and Jackals to steal from (not to
> mention the fact that Hyenas often hunt for them selves anyway).

That's not valid.  What, bone crushing jaws aren't an asset to predators?
Seriously!  And hyaenas are great hunters.  The problem is that they hunt
at night, when camera crews aren't out there.  They scavenge during the
day, and that's all we see.  Lions have powerful jaws too, so do alligators
and sharks, and yet Horner doesn't compare T. rex to them.  So most modern
animals with strong jaws are actually mostly big game hunters!  Hmmm...
And vultures and jackals have small, weaker jaws.  Hmmm...

> As far as I
> know T-rex  does not have to share its environment with anything large
> enough to bring down large Edmotosaurs/Triceratops on a regular basis

Besides other T. rexes.

> to
> provide both itself and T-rex with a meal of endothermic proportions. And

> there is no way i'd believe that disease and flooding were so rampant
that
> there was a constant supply of carrion to sustain T-rex over the X
million
> years it rained over.

Scavenging sustains endothermic vultures.

> Maiasaura eggs and embryos and dinosaur growth
> rates, to name a few.

I'll let HP Rob Gay address this one.

To end I'll say this: there's no positive evidence for T. rex solely
scavenging, but there's positive evidence for T. rex hunting both big game
species in its environs.  The data's there for conclusions to be drawn from
it.

-Demetrios Vital