re: PARTICULAR sauropods aquatic?

[Jeffrey Willson <jwillson@harper.cc.il.us>]

"Matthew Bonnan" <mbonnan@hotmail.com wrote:

>Lastly, juvenile sauropods which were aquatic while they had terrestrial 
>parents would seem to be problematic.  Sauropods must have had big appetites 
>and may have migrated to satisfy their hunger.  
>How would the aquatic or semi-aquatic juveniles have following the
land-lubbing adults?

Well, it strikes me as at least conceivable that they *didn't* follow, at
least until they were subadults. Maybe the young stayed in the "nursery"
until big enough to keep up with the Herd. We've all seen the footage of
migrating wildebeest herds crossing rivers -- perhaps young sauropods
stayed there and were merely spectators to the annual migrations until the
day a certain hormonal urge prompted them to join.

And the idea of juvenile sauropods (sauropodlets??) being full members of a
terrestrial herd has always struck me as problematic as well -- even if
they could physically "keep up", a quarter-tonne juvenile is surely a very
different sort of animal -- a different niche, with different requirements
and problems -- than a multi-tonne adult? 
(Could an adult sauropod even *see* a nearby juvenile?) (Oh, sorry, kid ... )

Young sauropods must have been primo carnosaur chow, no? In fact it seems
pretty likely that the great majority of sauropod deaths by predation
occurred while they were still bite-sized. Two possible defense mechanisms
might have been: 1) stay in water where it was more difficult (*I do not
say impossible*) for carnosaurs to get them,  or  2) Hang out with several
hundred (thousand) tonnes of protective adults. Again, I'm not saying the
young *were* (semi-) aquatic, I'm just asking if there's any evidence for it.

Any evidence of juvenile sauropod's limbs or tails more or less well
designed for aquatic life?
(My understanding is no, not particularly well designed for this.)

What do the trackways actually say about the range of size of Herd members?

How do the freshwater aquapredators compare with carnosaurs? 
(Phobosuchus doesn't really figure into the sauropod question, as far as I
know.)

Jeffrey Willson <jwillson@harper.cc.il.us>