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Re: Origin of Birds-arboreal biped



Dinogeorge wrote:
>In a message dated 97-12-17 05:37:13 EST, sarima@ix.netcom.com writes:
>
><< > Their
> >feet are
> >built for >both< running and climbing.
> >
> Do tell.  _Peromyscus leucopus_ runs up trees without even slowing down.
> And I believe I have seen it meadow relative, _Peromyscus maniculatus_
> actually climb *grass*.  (Big Bluestem is quite a robust grass).>>
>
>About a month ago while walking our dog in San Diego's Balboa Park, we watched
>a >lizard< do exactly this: run up a tree without even slowing down. Such were
>surely the ultimate predecessors of birds.

I have seen goanna's up to a meter in length climb trees with ease.  They
do it to take advantage of any breeze and to raid bird nests.  Not only
that they are quite happy to generally hug the trunk at an angle of 90
degrees rather than rest on branches, yet no-one had described any
morphological adaptations for aborality in goannas!

Chris


cnedin@geology.adelaide.edu.au                  nedin@ediacara.org
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Many say it was a mistake to come down from the trees, some say
the move out of the oceans was a bad idea. Me, I say the stiffening
of the notochord in the Cambrian was where it all went wrong,
it was all downhill from there.