Re: Resources, energetics and dinosaur maximal size

[Jura <pristichampsus@yahoo.com>]

--- On Mon, 7/27/09, David Marjanovic <david.marjanovic@gmx.at> wrote:

> From: David Marjanovic <david.marjanovic@gmx.at>
> Subject: Re: Resources, energetics and dinosaur maximal size
> To: "DML" <dinosaur@usc.edu>
> Date: Monday, July 27, 2009, 4:43 AM
> So Thunderbird does not automatically
> insert line breaks when quoting (the way Outlook Express
> does). I'll try doing it by hand... :-(
> 
> > If the food intake of the largest herbivorous mammals
> defines the maximal rate at
> > which plant resources can be consumed in terrestrial
> environments and if that limit
> > applied to dinosaurs,
> 
> It doesn't. Sauropods didn't chew. Evidently McNab has
> never seen a sauropod mouth.
> 
> This, the third sentence in the abstract, is the point
> where the paper turns out to be a failure of peer-review.
> <sigh>

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Quite the contrary. McNab does talk about the argument of sauropodan "hoovers." 

McNab wrote:

One way that herbivorous dinosaurs might have had a higher Kh [maximal daily 
field expenditure] is if they swallowed their food without mastication, whereas 
herbivorous mammals chew their food, which limits food intake. However, the 
rapid swallowing of coarse food is unlikely to increase Kh, because the 
limiting factor on food consumption then would be
the rate of fermentation in the gut, which is reduced by swallowing 
unmasticated fibrous food, the time required for fermentation increasing with 
food intake and body mass. Thus, the huge abdominal masses of sauropods were 
undoubtedly large fermentation vats that may not have completely compensated 
for the absence of buccal processing of food. So, it is unlikely that Kh was 
appreciably higher for dinosaurs than for mammals, either because of greater 
food abundance or because of a higher efficiency in processing food, and thus 
could not account for their larger masses.


Jason