Re: late night thoughts: adults only

[don ohmes <d_ohmes@yahoo.com>]

I know nothing about many things, and the mechanics involved here are 
definitely one of them. But you're right, that is a key question. Wonder what 
the sleeping posture was (if any)? 

The cartoon I had in mind was sort of a 'squirrel chewing a nut' posture, only 
w/ the tail flat on the ground. That would place the jaws as high off the 
ground, or higher, than they would be when walking. Although I have no idea if 
such is actually feasible.

Anyhow, I do not think the apparent neat fit made when certain famous long 
skinny necks w/ little tiny heads are placed between those monster jaws is a 
coincidence, although I realize that doesn't necessarily count much as 
evidence. 

What I do feel fairly certain of; the probable near-incessant foraging required 
to keep a sauropod body fed, combined w/ a fragile slender neck held nearly 
parallel to the ground, made them tactically vulnerable to tall, patient bipeds 
w/ powerful jaws. I feel the extreme predator/prey weight differential can be 
safely ignored and the behavior required of the predator is not overly complex. 

Can you imagine? Your skinny neck is 10m long, and is buried in a stand of 
trees as you forage busily (large herbivores can get very pushy); when you spot 
a squatting T. rex equivalent 5 or 6m away from your head, your options are 
limited. Your only reverse gear is double-granny low, sideways motions of the 
head are probably constrained by vegetation, and if you lift your head up 
suddenly, you pass out. 

(<snap!>) 

I understand that consensus is that when T. rex proper was in full flower 
sauropods were getting kind of scarce... might have been one prey/predator race 
where the predator won. Maybe Horner is right in that they were down and out at 
the end; but only if they had run out of the good stuff, in my opinion.    }:D.


Don



----- Original Message ----
From: Dann Pigdon <dannj@alphalink.com.au>
To: dinosaur@usc.edu
Sent: Thursday, June 7, 2007 10:21:15 PM
Subject: Re: late night thoughts: not all T. rexes were adults

don ohmes writes: 

> Hard to see, specially at night. Although the feathers are a bit much... also 
> highly important to my simple mind is the ability to adopt a tripodal 
> squatting pose that can be held effortlessly for hours. Anybody got a clue on 
> that last?

The huge pubic boot of tyrannosaurs would seem to indicate that a long-term 
squat wasn't out of the question. The big question is; how quickly could a 
tyrannosaur rise up out of a squat? 

Perhaps if it rocked back on it's pubic boot (putting more weight 
temporarily onto its tail) while straightening it's legs, then it's head 
would be coming down and forward at the end of rising (good for an immediate 
strike with the jaws). If it rocked forward however, raising the tail first, 
then the head would be moving up and back as it completed rising, meaning it 
might miss an opportunity to snap at whatever disturbed it. 

Camels get up backside-first (throwing the occasional unsuspecting rider 
over its head). I think from memory that horses get up backside-last. What 
would be easiest for a tyrannosaur? Given the tiny forelimbs, I'd think 
head-first / backside-last would be the better option when rising. 

___________________________________________________________________ 

Dann Pigdon
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://heretichides.soffiles.com
___________________________________________________________________