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RE: Long Horizontal Necks Re: Vertebrae of Early Sauropods



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