Thanks Cofty, for explaining it so clearly and simply. I'm not knowledgeable at all on these topics, but I remember a chapter on one of Dawkins's books on bats and echolocation which fascinated me as well. This thread subject reminded me of that and also of the fact that some birds of prey have amazing eyesight.
Evolution fits perfectly with a world in which some animals needed to hunt to survive and thus evolved traits that aided them in that and other animals which evolved in ways that helped them better escape their predators. This had always caused me cognitive dissonance when I was in the cult.
The natural world is full of many interesting animals and understanding how evolution moulds it all is very exciting indeed.