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Re: Origin of flight



On 9/14/07, Mike Taylor <mike@indexdata.com> wrote:
> Dann Pigdon writes:
>  > Vertical pounces take advantage of that blind spot, plus I imagine
>  > that using gravity to accelerate the predator's mass towards the
>  > prey (and then crushing them against the ground) is probably more
>  > energy efficient than a horizontal leap (where forces are generated
>  > by muscles alone).
>
> I find that hard to buy, unless you're talking about predators that
> climb a tree beforehand and then drop out of it.  If you're just
> talking about a high-trajectory leap then the force available to the
> predator to crush the prey on landing is precisely the force it
> generated itself when it pushed off from the ground (less air
> resistance, friction and sales tax).

Indeed.

However, crushing the prey into the ground is surely preferable to
whacking it more or less horizontally in terms of preventing it from
getting away. The prey we're talking of are too small to be very much
inconvenienced by being knocked over, so the impulse you give it by
hitting it from the side may be little more than that much of a head
start for escape.


-- 
Andreas Johansson

Why can't you be a non-conformist just like everybody else?