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RE: BRACHIATING (fwd)



Dwight Stewart
                                                         VLSI
CVD/DIFFUSION ENG.
PHONE: 522-7164
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Email: dwight.stewart@vlsi.com <mailto:dwight.stewart@vlsi.com> 

        -----Original Message-----
        From:   Richard W Travsky [SMTP:rtravsky@uwyo.edu]
        Sent:   Monday, August 10, 1998 11:14 PM
        To:     dinosaur@usc.edu
        Subject:        RE: BRACHIATING (fwd)

        This digresses from dinosaurs but it's an interesting topic. 

        On Mon, 10 Aug 1998, Jim Choate wrote:
        > > From: "Stewart, Dwight" <Dwight.Stewart@VLSI.com>
        > >  I believe the latest theory on hominid bipedalism is that it
was a strategy
        > > for standing taller in order to look out for predators.  It USED
to be
        > > thought that it was necessitated in order to have the hands
free.
        > > Richard Leakey has done a lot of work on this.
        > 
        > So what happened to the theory that it was related to cooling? Any
pointers
        > to its downfall?

        Cooling would've come after a committment to bipedalism. You can
always
        keep cooler just by staying in the shade or staying out of the sun
during 
        the hotter parts of the day.

        One of the cable channels recently had a thing on chimps that
included
        footage of bonobos. There was film of them walking upright, carrying

        things (food). _This_ was spooky to watch.

        IF I understand it correctly, the hypothesis is that carrying items
exploited an already upright stance.  BTW: Donald Johannsen vehemently
disagreed with Leakey! :-)  

        Watching for predators or food? Hmmm.

        Now, what ecological niche would be exploted by an upright stance?

        In this vein, it often seems to me that most dinosaur predators 
        were bipedal, even small ones. Something similar in their
lifestyles?
        Predation?

        Rich
        That's an excellent point!  Wasn't there a larger percentage of
early Triassic quadrapedal predators?  Most dinosaur predators (or even
scavengers, if you agree with James Horner) were bipedal.  Speed is not
necessarily a feature of bipedalism in mammals, but dinosaurs APPEAR to be a
different model.  Of course, bipedalism might be coincident with predator
status and not causative?

        Dwight