Am 28.09.2011 10:37, schrieb Mike Taylor:
On 27 September 2011 22:27, David Marjanovic <david.marjanovic@gmx.at> wrote:
>
>> That would be one of the few things that Kent and we WOULD agree >> on. Assuming that brachiosaurs drank, they would have needed the >> ventral flexibility to get their heads down to ground level. > > I assume their shoulder mobility didn't allow the giraffe > workaround to this problem? [...] ... and now I realise you were talking about flexibility of the forelimb, right?
Yes. Giraffes are _not_ able to reach the ground with the head while standing normally; they have to sprawl their forelimbs. Thus, all else being equal, we can't simply assume that sauropods _must_ have been able to reach the ground. My question was how much else _was_ equal: were sauropods able to sprawl their forelimbs? Apparently, *Brachiosaurus* was the only one.
Of course, the sheer number of neck vertebrae makes me confident that sauropods were easily able to reach the ground, and if not, there's the remote possibility that they didn't even need to drink -- various desert mammals manage this today, and that without the ability to pee uric acid crystals. My point is just that it shouldn't be an unquestioned assumption that sauropods were able to lower their heads the ground while standing.