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RE: Diplodocus: Return to the Swamps????
On Tue, Dec 15th, 2009 at 4:45 AM, Michael Erickson <email@example.com>
> But... Why mud at all? Couldn't sauropods have favored bodies of water with
> sand and/or gravel,
> rather than mud? You know, big sandy- or gravelly-shored lakes rather than
> mucky bayous.
I have a hard time imagining sauropods submerging themselves in *anything*.
through those long necks would have been hard enough at the best of times.
pressure around the lungs wouldn't have improved things.
Of course, just because I can't imagine something doesn't mean it didn't
The 'power' of sauropod muscles has been mentioned as a way for them to
bulldoze their way
through (or out of) mud. Exactly how much muscular power would sauropods have
Most modern reconstructions have them with surprisingly little muscle mass for
their size (forget
those old 'chunky' sauropod toys). Here's a sort-of-modern (1980s?) GSP image:
Muscles in organisms are a bit like rocket fuel in rockets; the more you have,
the more you need
just to move it's own weight. If modern sauropod muscle reconstructions are to
go by, it would
seem that many sauropods had enough muscle to get around (slowly) in optimal
but not a lot extra. It's not like they needed to jump, or propel themselves
around at a gallop.
Another reason I think it unlikely that sauropods *prefered* swampy areas has
to do with cost
verses benefits. Sauropods had tiny mouths for their size, which would have
restricted the amount
they could eat per unit of time. This in turn would suggest metabolisms
considerably lower than
those found in other dinosaur lineages.
Modern elephants avoid steep terrain if possible, due to the fact that they
burn %2500 more joules
moving vertically 1m than they would moving horizontally the same distance. If
you burn more
joules finding food than that food then provides for you, then you starve to
Wall, J., I.Douglas-Hamilton & F.Vollrath "Elephants Avoid Costly
Mountaineering". Current Biology
18(14) (PDf is online at http://www.savetheelephants.org/publications.html )
Elephants almost certainly have higher metabolisms than sauropods, and much
capable of consuming biomass more quickly. Yet they avoid overly strenuous
modes of transport
(climbing slopes) where possible, as it's energetically wasteful. I imagine
(there's that word again)
that plowing through mud would require much more energy than walking up sloping
(depending of course on the degree of slope). Would sauropods have been able to
spare all that
extra energy? Perhaps if it meant the difference between immediate
life-or-death, but somehow I
don't see them pushing their way through swamps (or even deep water) on a
GIS / Archaeologist Australian Dinosaurs
Melbourne, Australia http://home.alphalink.com.au/~dannj