Re: gigantism as liability

[David Marjanovic <david.marjanovic@gmx.at>]

> It depends on what sort of metric one uses - large size invokes special 
> mechanical constraints, and thus represents a sort of biological 
> "solution" to interesting problems.  At the same time, I agree with your 
> sentiment that "bigger is better" is a subjective tendency that probably 
> clouds some analyses.  Particular size ranges are only "best" in the 
> context of specific circumstances.

Sizes larger than those achieved by terrestrial mammals have two manifest 
advantages, off the top of my head: animals with such sizes can live off 
very poor fodder by simply eating more of it, and "humungous animals get a 
lot less predator attention than large ones" (Mark Witton).

> One of the primary size effects is probably seen in neonate size, in fact, 
> more than adult size - sauropods apparently maintained a relatively 
> "r-selected" type breeding strategy in terms of juvenile size, juvenile 
> growth, and clutch size.  This probably works very well under a wide range 
> of conditions, but may become a liability under specific circumstances.

Such an r-strategy allows a species to survive the complete extinction of 
all adults. Maybe that's why the sauropods were such a success story, 
surviving the Triassic-Jurassic, Jurassic-Cretaceous, Aptian-Albian, 
Cenomanian-Turonian and probably a few smaller mass extinction events.