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Re: Sprawl, speed etc

>Sorry, I'm a bit lost with these sprawl/upright mixes/speeds/stances. Rob, I 
>think, has said that sprawled front limbs add stability and a sprawl means an 
>aniimal does not have to slow down in a turn, whereas an upright animal does 
>not. Having spent a good deal of time on horsback (and being thrown off) I can 
>assure you that an upright animal does not loose speed on a turn; it simply 
>"changes foot" ie adjusts its pace to lead with the foot that is on the 
>of the turn, leans over so that centrfugal forces (laymans term?) holds it in 
>place on the turn, and carries on running/galloping/whatever. Equally it does 
>not loose manoeuvrability; it uses a hind foot to pivot (and can do this so 
>unexpectedly/fast that the rider falls off). 

True.  However, based on automobile test runs, it has been shown that the
farther out one puts the wheels, the better the handling (take a look at some of
Chrysler's new models, for example).  This doesn't mean that a high speed/erect
posture animal won't be able to evolve adjustments to a more upright form, just
that the upright form will be more unstable (creating different opportunities).
This is simply adapting to differing evolutionary pressures.  I suggest that the
ceratopians were simply more *efficent* at high speeds, due to their inherent

>I don't understand Rob's concept of "dune busting" at all. For an animal to 
>survive on  soft surface it needs big big feet to stay _on top_ of that 
>The only reason I can see where a sprawl would help would be where the 
>of its feet got so large they would collide with each other if held under the 

I'm afraid that dune buggy manufacturers disagree.  Tires on these vehicles only
make contact with the ground at four relatively small points (relative to
vehicle size).  I simply make the suggestion that the two morphologies are
analogous to each other, evolving/designing to overcome the same conditions.

>An aside............
>As a layman, I find it difficult to understand sometimes why animal/(read 
>behaviour is seen as primitive/simple/unsophisticated. Surely _any_ animal 
>survives for successive generations (ie successfully) is de facto an exhibitor 
>of extremely complex behaviour/adaptation in relation to its environment? 

Exactly my point.


Q.  What fossil fish is a blood relative?

A.  The antiarch.