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Re: cause of Gigantism in sauropods
Excellent points all around. I actually had the Hone and Rauhut paper in mind
with some of my comments, and should have cited it in turn; thanks to Augusto
for doing so (those that have not read the manuscript, I highly recommend doing
so - I have David Hone's contact info for those searching for a copy).
In any case, the observed clutch sizes and histological data demonstrate an
r-selection strategy type life history, as you noted, which would necessarily
imply a large biomass of juveniles unless hatching rates were very poor.
Assuming that roughly the same proportion of eggs hatched as in modern
oviparous species, there must have been a huge number of neonates. While many
of these undoubtedly died very small, we know that they grew into the
"mid-range" sizes quickly (histological data), so it seems reasonable to assume
that a significant number of juveniles at all growth stages were present.
On Feb 9, 2011, at 2:52 PM, Augusto Haro wrote:
> 2011/2/9 Habib, Michael <MHabib@chatham.edu>:
>> Personally, I don't understand the insistence that theropods must have been
>> attacking prey many times their own size, risking death in the process, when
>> evidence suggests that there was a huge biomass of smaller available prey
>> (especially juveniles) available for consumption.
> I also believe theropods mostly ate small prey, including juveniles of
> larger herbivorous dinosaurs, following the paper by Hone and Rauhut
> (2010). It may better deal with the perils of getting the head crushed
> as you say, or fall when running after adults, or facing armored and
> probably dangerous prey, as many common larger ornithischians. But, as
> far as I remember, they said predation of juveniles explains the
> scarce preservation of dinosaur juveniles. In such a case... what is
> the evidence supporting the viewpoint there were so many juveniles? I
> think that inferred precocial R-stategies may be some indirect
> evidence, and also sustaining a population of large theropods which
> cannot rely on larger stuff, but arguing this would be circular
> assuming we suppose theropods hunted small juveniles because of their
> Hone, D. W. E. and Rauhut, O. W. M. (2010), Feeding behaviour and bone
> utilization by theropod dinosaurs. Lethaia, 43: 232–244.
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