RE: Long Horizontal Necks Re: Vertebrae of Early Sauropods

["Eric Martichuski" <herewiss13@hotmail.com>]

> From: Mark Hallett <marksabercat@yahoo.com>
> To differ with you on this, Eric, why would walking be
> more stressful for a sauropod than swinging its head?
> Are you speaking here of caloric expenditure when you
> say "stress"? Moving towards a standing food source
> consumes only a trivial amount of an animal's energy
> (even less for large animals,which although their
> absolute caloric expenditure is greater than a small
> animal's, is less in proportion to their size).

I was thinking more along the lines of spikes in blood pressure, but caloric 
expenditure works as well.  In order to move from one clump of foliage to 
another, the sauropod can either

A) move it's entire multi-ton bulk...and then do it again for the _next_ 
clump, and the one after that; all of which engages a large number of 
muscles and puts added strain on bones, tendons, etc.

or

B) move its much lighter (relatively) neck...and this movement can suffice 
for a great many clumps of foliage before a step needs to be taken.  In 
contrast, think about how much movement the _entire_ body of, say, a zebra 
would have to undergo to graze through as much plant life as a single 
neck-sweep would cover.

Obviously, the sauropod is taking a lot of steps anyway (i.e. all the 
trackways we have, etc.), but given that it _appears_ to be living close to 
design limits in a number of ways, it only makes sense to reduce the strain 
on those limits when possible.

I'd actually thought this feeding strategy was already accepted as a given 
for some species.  Obviously much less connected to current thinking than 
I'd assumed. ;-)

I do accept your other statements without quibble, however. ;-)

Eric
______________________________________________________________________
"There is no other wisdom,
And no other hope for us
But that we grow wise. -- Diane Duane
______________________________________________________________________

_________________________________________________________________
All the action. All the drama. Get NCAA hoops coverage at MSN Sports by 
ESPN. http://msn.espn.go.com/index.html?partnersite=espn