Re: Theropod limbs - how mobile?

["no go" <honkietong@hotmail.com>]

> 300 LBS = ?150 Kgs. Impressive as that is in human terms, it is weak in 
> T.rex terms. T.rex's would weigh between four and eight tonnes (depending 
> on the estimate and the individual); when it moved or stood up we are 
> looking at many tonnes of force, not kilograms (or LBS). I can't see 
> T.rex's arms being used to hold a female during mating, they would be 
> ripped off. As for gripping carcasses, why? Why would it want to hold a 
> carcass to it's chest? Even if it did, it could only hold relatively small 
> chunks, because again, it's prey were also multi-tonne animals.
>
> Is it possible that the heavy musculature on tyrannosaurid arms was simply 
> retained from ancestors, and didn't serve any function?

It is entirely possible that the reason why the arms were so powerful in the 
first place, was because the area of the body that supported them were 
powerfully muscled as well. Tyrannosaurid forelimbs are relatively 
inflexible in the first place and I don't see why it could not use its mouth 
(which would have been much stronger and the focus of action in 
Tyrannosaurids) at carrying food. The mating idea is old but prehaps not as 
unfeasible as it seems, they could be useful to position the animals between 
consenting individuals, though they would be of limited use once things got 
rough. However the fact that some Tyrannosaurid forelimbs do indeed show 
injuries and damage such as tendon advulsion (my spelling is leaving me) 
does indicate they could be using their forelimbs somehow, powerfully at 
that. Unless we get to see some amazing documentry involving real life 
Tyrannosaurids ("Big Tyrannosar Diary"???), we can never be sure.

I wonder if those tiny forelimbs could be used as display structures to 
indicate interest or threat. Heck, I wonder if rexy could have used those 
tiny two-fingered hands of his to show off obscene signs to other dinosaurs, 
roaring at the same time "I'm the meanest @%$%#^!!! in this land! One more 
smart-alek remark about my arms and I'll bite your head off!!!" But I 
digress...

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