good horse can out-pull several men. A homing pigeon can be carried a hundred miles in a cage, be released, and find its way quickly to its home loft. A fly can walk upside down on a ceiling. A tiny hummingbird poised to dip its beak into a flower makes a modern airplane look like a clumsy contrivance.
But here's the difference, as I see it. If this earth were inhabited only by dogs, horses, and birds, it still would be uncivilized. The thing that has enabled us of the human race to achieve what we call "progress" has been our ability to talk. That means, to exchange ideas and information. And when those have been passed from person to person, and from one generation to another, civilization appears. The factor