Subject: Re: How did T. rex scratch its back?
From:

Cal King wrote:

In article <33F25913.D35@umail.umd.edu>,

Holtz,

Jr. ) wrote...

The latest work (still unpublished) on T. rex forelimbs suggests it

strong grip. Even so, it had very limited mobility. Suggestions for

include:
stabilizing prey while feeding;
display function;
grappling the female during mating (this one goes back to Osborn);
nonfunctional.

It is hard to test any of the above hypotheses at present.

My hypothesis: A massive pair of forelimbs would probably topple the

bipedal

T. rex over easily since the center of gravity may then be shifted too

high,

especially since T. rex already has a massive head. Forelimb

may be

an adaptation for better weight distribution. Reduced forelimb mass

lowers

the center of gravity and alleviates the need for an unwieldly large

as

counterweight.

Well, many of the large predatory dinosaurs had similar length, but much
more muscular forelimbs (Acrocanthosaurus, Giganotosaurus, etc.), and
comparable-sized Deinocheirus and Therizinosaurus had HUGE forelimbs.

course, Deinocheirus (an ornithomimosaur) and Therizinosaurus (a
therizinosaur aka segnosaur) had smaller heads than the large predatory
forms, but they had quite substantial necks to deal with.

T. rex (and many bipedal dinosaurs) may have converged upon
the modern day kangaroo in forelimb reduction, if not in locomotion.

Actually, many types of kangaroos have sizable forelimbs, but I agree
with the basic concept here.

I surmise that T. rex probably subdues its prey with its jaws while

foreclaws dig in and cling to the prey's body for balance, in much the

same

way that lions do.

See "stabilizing prey while feeding" in my list above.

The sharp claws on the hindlimbs may tear its victim's
abdomen while its jaws maintain grip.

Tyrannosaurid footclaws are (contrary to popular opinion) NOT very sharp
when compared to Allosaurus or other large predatory dinosaurs. They

blunter (although not quite as blunt as in ornithomimids).

In order to reach the neck vertebrae of
its tall vegetarian prey, T. rex has to be tall.

The prey of T. rex (hadrosaurids and ceratopsids) were not terribly

Hey! What about triceratops?

Although the sauropod Alamosaurus occurred in the southern part of T.
rex's range, it was probably not a major part of the diet of the

over its whole range.

Heck, may be I am eligible for the Nobel prize for solving(?) -- or at

least

guessing correctly -- the mystery of T. rex's little arms.

Sorry, no Nobel for paleontology (*sigh...*)

I LIKE TO THINK OF THE TYRANNOSAUR..

I like to think of the Tyrannosaur as a solitary beast,
Alone by choice and nature, aloof and so proud.
Á terrible arrogance and blazing omnipotent self
With room for no other.

I like to think of the Tyrannosaur as quite smart
In an evil kind of way
Most cruel and predatory cunning
A clawing sense of self; an expression of power
From the egg.

I like to think of Tyrannosaur coupling
As a rape -
A midnight ambush:
Bellowing- Hissing female in a grip
Moonlight shattered trees and dustclouds; the thunder of the earth.
And a rape.
(Male stalks contemptuous away thereafter)

I like to think of gawky young teenage Tyrannosaurs
Brutally rejected from the nest
Endless oafish savageries of sibling spite
Forgotten nor forgiven
Each alone.

I like to think of a tough and thuggish young apprentice
Tyrannosaur;
Only eight foot tall but rough and strong and smart
And ruthless-cruel -
Killing the locals.

Carving out a territory of (her) own
Plotting at the hated scabby weakling wrinkled ***** ...
In possession.
(She won't live forever...

I like to think of the monstrous young adult Tyrannosaur
Newly Victorious;
Grinningly scenting the air.
Cool and Cruel and battle-scarred and canny
- Knowing.

Hot blood erotic through every throbbing artery -


Ready to kill.

***

Grantland

You go Grantland - you go on about it
all with great chastizement and vigor.

Now to get back to the question of the subject. The T.rex used a back
scratcher
that he had carved for his own personal use from a giant mahogany.

Somewhere on my website I have a animated picture of the T-rex doing this.


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