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Re: Fw: Dinosaurs and birds
----- Original Message -----
In any case, the point Jim was trying to make is that the speed of a
running (bipedal) animal is largely limited by mechanics of the hind limbs
and their interaction with the ground.
Adding thrust from the forelimbs will only add speed if the hind limbs can
keep up. They generally cannot if the animal is already at a sprinting
gait, so forelimb-assisted speed increases don't tend to be very feasible
for birds. This is one reason why running birds don't deploy the wings
unless they are launching, or engaging in a ground maneuver for which an
additional force vector might be helpful in maintaining balance.
That does not rule out maneuverability and balance being enhanced by
forelimb dynamics over level terrain, and these will obviously bolster
forward progression indirectly.
Yeah. When my dad was teaching me to play tennis, he spent many hours
working on how I used my arms and racket to help me maneuver and change
direction while running (or at least, to minimize their hindrance -- I'm
pretty much a klutz now, and was then as well).