>Don't forget sweat glands. (Not that that solves any real problems.)
There an article in _Analog_ a several years ago called "The Long Stern
Chase" (I forget the author) which suggested that the capacity to sweat is a
filter too [pardon the repetition if I wrote about this here before]. It's
reaching, but goes like this: 1) sweating permits the hunting of the type
described in the title. Big cats rely on bursts of high speed to bring down
prey, but human track and chase. Sweating is an important adaptation to that
kind of activity (horse's sweat, but it doesn't seem to be as effective at
cooling them down). 2) Along the way we learned to concentrate on achieving
goals for hours at a time, which is just as important for developing
technology as intelligence and hands.
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Sean Morgan (sean@lucifer.com) | All progress is based upon a universal
| innate desire on the part of every organism
http://www.lucifer.com/~sean/ | to live beyond its income. -- Samuel Butler