Re: gigantism as liability

[Erik Boehm <erikboehm07@yahoo.com>]

> The article's authors count gigantism as
> some sort of achievement...one that mammals have been unable
> to attain.
This was limited to terrestrial mammals right? Blue Whales are the obvious 
exception, being the largest living things known ever, correct?
With the advantages previously mentioned of living off of poor food 
(plankton/krill) and relative freedom from predation.

I doubt this has anything to do with mammals, and more with suitable ecological 
niches.
Mammals are the dominant terrestrial animals, but aren't the only ones, no 
other extant terrestrial lineages show gigantism.

Dicynodonts got pretty big in the Triassic didn't they? Mammals certainly are 
better adapted to large size, at least concerning posture -erect limbs will 
support weight better, yet it seems previous synapsids became larger than the 
extant ones.

I wouldn't be surprised if one were to take certain mammalian lineages, and 
somehow put them back in the triassic, that those lineages would evolve towards 
gigantism.

But I think that niche on land has been closed for now, or at least a niche for 
a suitable transitional form to lead to the occupation of a gigantism niche.

Could pack hunting behavior be a recent development to explain it?

Is there something limiting a larger predator from being viable? such that 
large mammals like Hippos, Elephants, Rhino's, etc are under minimal selection 
for increased size?

Such animals suffer minimal predation - adult elephants are really only 
threatened by packs of lions if they are seperated from the herd - which means 
things probably weren't going well for the elephant anyway.

> Bigger is more awesome, and therefore better.  
> All right-thinking people will immediately see the truth of this.

Sarcasm?