We seem to be Hell-bent on replacing everything and everyone ... just because we can.

I hear you, however I remember the words of a NASA scientist who was working in the biomechanics division. She was trying to come up with an exercise machine that would work in zero gee, and she said something along the lines of;

"We're trying to mimic nature because that right there is 4.5 billion years of R&D, so who are we to say we can come up with a better structure?"

Something like that, but you get the point... As for robot dogs, I'll stick with my real one for the moment, at least he doesn't short-circuit when I give him a bath... well kind of not! :-)

Cg