Re: Bipedalism

[rjmeyer@ix.netcom.com (Rob Meyerson)]

Dinogeorge writes;

><< Then, is bipedalism simply a feature of an arboreal lifestyle? >>
>
>No, not a feature of it, but in the case of theropods, an expectable result of
>it. Many of the relatively few extant bipedal vertebrates that are not birds
>(such as ourselves) seem to have had arboreal ancestors.

I was thinking about this last night and had another idea.  Virtually all 
extant arboreal animals are "forced quadrepeds" (for lack of a better term).  
Whether it is a sloth, an iguana, or a spider monkey, these critters have all 
their limbs grasping the branches (tails included for the monkey).  This makes 
a great deal of sense; every limb that has contact with the tree reduces the 
animals chances of falling.  I wonder if bipedalism would be a detriment, and 
possibly fatal, for an arboreal animal