Re: origin of bats/reply to J. Headden

[David Peters <davidpeters@att.net>]

On Jun 20, 2008, at 4:29 PM, Jaime A. Headden wrote:

> David Peters (davidpeters@att.net) wrote:
>
> <Unfortunately, Jaime, you're thinking only of upright bipeds. All  
> bats are inverted.>
>
>   They don't walk upside down, do they?

No one said bipeds have to walk.

For some reason, crinoids just came to mind.

> Because if they did, that would be something. But from what I  
> understand, even if they CRAB-WALKED sideways, this is a form of  
> movement wholly unlike anything any other biped has ever done, and  
> would result in different constraints on movement and NOT result in  
> the features that all other bipeds tend to share. it would not, for  
> example, result in anything like the pelvic and femoral features  
> relating to bipedalism.
>
>   Note that most especially, bats are sprawlers.

Except when they are inverted.


> They can only bring their legs into parallel while 1) in flight,  
> and 2) while in suspension. This is not something that looks like  
> they can do while NOT being forced into it by whatever environment  
> they are in or attached to.
>
>   Note that others have criticised this consideration of bipedalism  
> in bats by constraining the topic to gait (or rather, locomotion),  
> for which the nature of bipedalism is linked. Bats have no gait  
> using solely the hindlegs, they simply hang upsidedown by them.  
> Maybe they'll inch sideways on a branch or a ledge, but this is not  
> a locomotion of any sort, any more than hanging by your hands and  
> inching along is a gait. It would not provide a constraint unless,  
> like oragutangs, locomotion was selected for in this fashion, and  
> in this case, orangutangs move forward on their arms, not sideways  
> a few inches, and cover a good deal of distance and using a good  
> deal of speed doing so. This would be a locomotory style, and has  
> its own gaits.
>
>   Cheers,
>
>   Jaime A. Headden

David Peters
davidpeters@att.net