Hidden depths

Along this rock platform are deep rock pools with all sorts of mysterious beasties hiding in them.  I did take care to not step in one.  I could see me having an unexpected dunking if I didn't watch out.  Rather nice clouds to the South East and a crescent moon to the right of this setting in the west.

You can't see them but there were about 5 dolphins heading north as I looked out here.  Why do they do their jumps for me in low light conditions when I haven't a chance of catching it?