P3D Animal Stereopsis

[Dylan The Hippy Wabbit <spacey@xxxxxxxxxxxxx>]

Hi All,

Tony Alderson wrote:-

>I'm no anthropologist, but my impression from my generalized reading is
>that our line had stereovision well before we started hunting other
>animals. And before we got "smart" too. Many of our primate cousins are
>vegetarian. And the earliest homonid hunters were pretty low on the
>pecking order--we were prey ourselves pretty often.

There are two circumstances that typically lead to the eyes migrating to
the front of the head.  One is a predatory lifestyle, as with dogs cats
and hawks etc.  The other is living up a tree, it's *really* useful to
know for sure where that next branch is.  All us primates have front
facing eyes right back to the most primitive, the lemurs.  Even so, most
Orang Utang skeletons examined have shown signs of old fractures.

It's also true that those who get preyed on a lot have their eyes set as
far apart as possible.  A rabbit has a very narrow band of overlap front
and rear.  Not too hot for judging distances, but they are damned hard to
surprise.  Of course, where the rabbit runs to is less important than
where *from*.  ;-)

You might imagine that squirrels have a problem in that case, having an
urgent need for both.  They appear to have settled on a half-way
condition.

Dave Spacey

_____________________________________________________________________________

Of Bill Gates, "In fact, he's Ernst Stavro Blofeld as played by Woody 
Allen." - Charles Shaar Murray


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