Originally Posted by brucehawsker
does anyone know why they behave like that?
As Cod points out, many believe it's simply because they can! I was fortunate to have been involved in some dolphin research many years ago when I lived in the Bahamas. They really enjoy interacting with humans and appear to have great fun playing with each other.
As for riding bow waves, I think they sense the pressure from the bow wave and ride it in much the same was a bird would ride a thermal... It's amazing how fast these animals can move in the water. If you ever have an opportunity to dive with them, it'll be a highlight of your life!