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RE: Aw: RE: Arboreal Theropods: The prize at the bottom of the cracker jack box



Dale Mcinnis wrote:

>Is there even a modicum of consensus as to WHY small theropods hit the arboreal
>life in the first place ?? What was the prime >motivation here ?? 

Predator avoidance is the most plausible -- specifically shelter during the 
sleep cycle, or as it is commonly referenced, roosting.

Trees are lousy places to hunt in, if you are a flightless quadrupedal predator 
-- the geometry is terrible, gravity assists target escape, stealth is 
problematic due to noise and vibration, particularly in the terminal branch 
environment -- but for those same reasons, they make excellent havens, assuming 
the talent for accomplishing the exploit of vertical ascent is present.

>From the flight evolution perspective, a point usually missed is that 
>rudimentary claw-climbing is much easier going UP the tree, especially a 
>vertical trunk. Downward claw-climbing requires an inherently laborious 
>reversal of the upward climb.

This implies that any aspect of external morphology that creates drag or lift 
enhances talent relative to the exploit of descent -- less energy is required, 
and, of course, jumping is simply much faster. 

And, trees are not bad places to hunt FROM -- perch-hunting is entirely 
plausible as a food-acquisition strategy.