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Re: back to science

On May 27,  6:33am, Colette H. Adams wrote:
> Subject: back to science
big snip

>  At the same time, their
> young could not survive on their own amongst the speedy, voracious
> predators of their day.  This precluded a lay them and leave them strategy.
>  (Actually, no living archosaur descendant to my knowledge has such as
> strategy, so it is doubtful whether any dinosaur did.)  The need for adults
> to feed at high rates meant that only a few babies could be cared for at
> any given time.

I suspect you're at least partly right here - the need to guard the
nest could restrict the number of eggs per clutch.  However, we have no
idea how many clutches they could produce - it is possible that parental
care ended at hatching at which point they would be free to lay another
one.  If infant mortality were high (probable) they might have produced
large numbers of young, but not in a single clutch.  I can't think of any
other vertebrate with LESS energetic investment in a clutch of eggs than
a large sauropod, and I doubt that energetics were a limiting factor.

I was under the impression that confirmed sauropod fossil nests were
extremely rare - is this so??

>If sauropods were not social, individual pairs would have
> had to care for highly vulnerable hatchlings for months at a time.

well maybe, but sauropods are not birds - there are other plausible
life history strategies

>The solution was to live in groups,
>with only one or two individuals in the group reproducing in a given

Now, this point bothers me, as it sounds like a group selectionist
argument - have I misunderstood?

 > Since adult sauropods had a constant need to be free of as much
> mass as possible, they would not have evolved viviparity.

Because no archosaurs, large or small, are known to have evolved
viviparity I suspect it is impossible for some reason.