Sharks. I used to have to swim home at night if I was the the last of 3 to call it a evening, we only had 2 dingys. The swim was about a 1/4 - 1/3 of a mile offshore & at 2:oo pm (when the bars closed or the music stopped) it would always start to get spooky about half way home. It was always comforting when I knew that dolphins were seen swimming close by. Always had a change of clothes & a swim suit in the car & could spend the night in it too if things got to spooky. If you asked a shark the same question they'd say dolphins, if you asked a dolphin they'd say not having any sharks around to have fun with. Barry