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Re: origin of bats/reply to J. Headden




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