Re: Terramegathermy in the Time of the Titans (not so long...)

["philidor11" <philidor11@snet.net>]

<What is the evidence for mass migration of hadrosaurs, sauropods, etc.?
The evidence is very indirect.  We assume that these large, supposedly
herding dinosaurs had feeding patterns and movements similar to large
mammals.  We assume that sauropods were clearing out regions of edible
plants in vast numbers, like gnus you
say.  We have footprints of sauropods all heading in the same direction.
But we don't really have any direct evidence for mass migration, or even for
the impact of dinosaurs on the Mesozoic environment.  Yes, they were big
animals, and yes we know that they must have had some impact on terrestrial
plants, etc., but no one has ever seen a feeding sauropod herd, or tracked
hadrosaurs on a migration across the Western United States.  We cannot
simply superimpose mammalian ecology on dinosaurs and say, "well, there you
have it."  It's much more complicated than that, because dinosaurs are not
mammals and they are very much extinct.  Our evidence for many of their
possible lifestyles and activities is very indirect.>

I suspect I'm only elaborating the comment by HP Norton, but isn't it
reasonable to suppose that, if these sauropods were herding, they would be
eating faster than the local plants could replace their edible parts?
Particularly if the climate changed unfavorably, even for a short time.
  This may not be a good argument for extensive migration, but it sure seems
reasonable to think that herding implies mobility.  Call it scheduled
wandering, whether a circuit lasting for a time or a movement to a distant
place at intervals.
  I'm always anxious to assert a test for logical necessity, and, in this
case, perhaps naively, the animals are so large that even slightly
commensurate food requirements do seem to imply mobility, necessarily.
Your turn to rebut an argument which must be based on logical necessity.