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Re: "Flight theory has legs"
Graydon (email@example.com) wrote:
<This can't be extended to aviform dinosaurs, though; they don't have the
basic mammal tree-or-ground-hugging-splat posture.>
Typical scanorial locomotion is not limited to trunk-hugging, but
extends to branch-walking, canopy-leaping, and so forth. Non-sprawling
arboreal/scansorial animals include the chameleontid lizards. The
non-sprawling posture, however, does not neccesarily limit the effect of
the manual AND the pedal claws on the same substrate. A semi-sprawling,
semi-hugging posture is possible, as first restored by Chatterjee, for a
spread-armed, tucked-legged position. I restore this to some degree on the
Dinosauricon, for elucidation (near the bottom of my gallery page).
Another version, featuring a vertical featherless *Deinonychus*, is also
available apart from *Sinornithosaurus* (but the arm position is
<Until someone finds quadrepedal bird tracks, I think the
no-substrate-contact is a pefectly decent assumption.>
No one is suggesting birds could be quadrupedal -- or extant birds, in
any case (I made a clear distinction in my prior post). Yet. I think
<I am also unable to come up with a hand-claw climbing scheme that
wouldn't involve the feet at all; the shoulder anatomy wouldn't let them
hang straight down from the hands.>
Well, if orangutans can, who knows. However, I don't think anyone
suggested that they could. Alos, if a bird hung upside down, belly up, the
arm position is not impossible for this, given claws.
Jaime A. Headden
Little steps are often the hardest to take. We are too used to making leaps
in the face of adversity, that a simple skip is so hard to do. We should all
learn to walk soft, walk small, see the world around us rather than zoom by it.
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
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