Re: Origin of flight

[Dann Pigdon <dannj@alphalink.com.au>]

Glen Ledingham writes: 

> Birds and small mammalian predators like cats and
> foxes often pounce with high leaps rather than the
> seemingly more efficient flat leaps, especially in
> tall grass.  Perhaps this gives them better vision of
> the prey and its evasive action or less resitance from
> the ground cover.

A vertical pounce reduces the chance of the prey detecting the predator (and 
thus taking subsequent evasive action). The eyes of most terrestrial 
creatures are designed to look about in a horizontal plane, rather that to 
detect attacks from straight above. 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). 

Most vertical pouncers detect prey with their ears, and may not actually see 
the prey at all before catching them. Arctic foxes and polar bears both use 
an attack from above to snare creatures hidden beneath the snow (voles in 
the former, seals in the latter). Cats and foxes hunting in long grass also 
tend to locate prey via sound. 

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Dann Pigdon
GIS / Archaeologist              geo cities.com/dannsdinosaurs
Melbourne, Australia             heretichides.soffiles.com
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