From: swf@teradata.com (Stanley Friesen)
Newsgroups: talk.origins
Subject: Re: Seismo/ultrasaur weights, was Holden and the galloping elephant
Date: 11 Aug 92 21:10:06 GMT
Reply-To: swf@tdat.teradata.com (Stanley Friesen)
Organization: NCR Teradata Database Business Unit

In article <2856@fedfil.UUCP> news@fedfil.UUCP (news) writes:
|In article <713399212@sheol.UUCP>, throopw@sheol.UUCP (Wayne Throop) writes:
| 
|> First, Ted's estimate of the seismosaur's mass is, as usual, off
|> by about 3-to-1.  Certainly *less* than 200,000 lbs mass is much more 
|> accurate than 400,000 lbs mass or *more*.  
|
|Bullshit.  Again, I would read McGowen's book.  He not only gives a 180 ton
|figure for the ultrasaur (that's 360,000 lbs), but a damned good explanation
|of how that figure is derived.  He leaves NOTHING to the imagination.
|
|The ultrasaur (the 360,000 one) was only 100' long.  The seismosaur was
|140'  long (see the July 91 issue of Popular Science).  I cannot think of
|any way in which the seismosaur at 140' could have been skinny enough to 
|weigh less than the ultrasaur at 100'.  They didn't have AIDS then.

That is because you do not know sauropod anatomy.

A brachiosaurid (which is what McGowan believed the ultrasaur to be) is
a *very* robust sort of animal.  It has a large *girth*, and volume, and
thus mass, is a funtion of the *square* of the girth.  Thus merely halving
the girth reduces weight by *75%*!  I believe that a diplodicid of comparible
length has a girht less than 2/3 that of a brachiosaurid.  Now let's see,
2/3 squared is 4/9, or about 45%.  Thus a diplodicid 100 ft long would weigh
(by McGowan's figures) about 80 tons.  At *most* a 160' diplodicid would
weigh 130 tons, but this assumes linear scaling.  A diplodicid would almost
certainly not scale linearly - most of the additional length would be in the
*thin* bits - the neck and tail, so a figure of 100 tons is really about
as high as you can reasonably go using McGowan's data.

But even then it turns out that estimating weights involves making a number
of assumptions on little data, so that errors of at least 20% could easily
be made.  This means that the Moroccan 'seismosaur' might weigh as little
as 80 tons.

|Drag a 400,000 lb blue whale onto land, and he suffocates, crushed by his
|own weight and unable to breathe.

Of course it does!  So does a dolphin (which weighs *much* less)!  This is
because the rib cage of these *aquatic* animals does not have the structural
strength of a terrestrial rib cage.

As for your weight estimates, why not try to place a reconstructed
seismosaur next to a blue whale, at the same scale.  You will see that
though they are about the *same* length, the seismosaur is *much* skinnier
(especially in the neck and tail regions).  Thus, by simple comparison it
*must* weigh far less than the 200 tons of a blue whale.

| The same thing would happen to any of 
|these large sauropods, were one of them to be so unfortunate as to be 
|dragged here in a time machine.
|
Nope, they had terrestrial ribs.

|(As before, Ted simply hasn't
|> acknowledged the difference between diplodocid sauropods and
|> brachiosaurid sauropods, which makes his position on the mass
|> of the seismosaur untenable.)

He still hasn't!
-- 
sarima@teradata.com			(formerly tdatirv!sarima)
  or
Stanley.Friesen@ElSegundoCA.ncr.com
Newsgroups: talk.origins