You cannot use a turkey you can a horse, as traction power and a militaray assault vehicle (cavalry, chariots). For some reason, American buffalo are are unsuitable for domestication.
The argument was put forth by Jared Diamond in his book _Guns, Germs and Steel_ and I must admit his environmental explanation of 'civilisational' differences go a very log way. Unlike conventional environmentalist who try to explain civilizational advances by environmental influences, Diamon explains the ABSENCE of certain advantages by unfavourable environmental influences, such as the absense of suitable species or geographic isolation.
The main point Diamond is making is that when you start in a relatively isolated and resource-poor environment, your civilisation will not get very far (that is, btw, the main lesson of the "Civilisation" computer game). However, in the Americas this argument takes a different twists, because the arrival of the stone age hunters coincides with the extintion of large mammals, which in all likelihood were hunted to extinction. Hence the line that an initial technological success (efficient hunting weapons and organization necessary to hunt big game) may later on turn into a relative disadvantage. That's dialectics, pure and simple.
I am actually very impressed by Diamond's argument. It is a heatlhy antidote to the culturalist tripe that nowadays passes for science.
wojtek