And yet the eagle will sit for hours on the crag and survey the kingdoms of the world until it spots a distant movement and then it will focus, focus, focus on the small shell wobbling among the bushes down there on the desert . And a minute later the tortoise finds the world dropping away from it. And then the eagle lets go. And almost always the tortoise plunges to its death . Everyone knows why the tortoise does this.
Gravity is a habit that is hard to shake off.
No one knows why the eagle does this. There's good eating on a tortoise but, considering the effort involved , there's much bet- ter eating on practically anything else. It's simply the delight of eagles to torment tortoises. But of course, what the eagle does not realize is that it is participating in a very crude form of natural selection . One day a tortoise will learn how to fly .