I came across this amazing story the other day of a pod of dolphins rescuing a group of swimmers from a great white shark.
"They started to herd us up, they pushed all four of us together by doing tight circles around us," Howes told the New Zealand Press Association (NZPA).

Howes tried to drift away from the group, but two of the bigger dolphins herded him back just as he spotted a three-meter (nine feet) great white shark swimming towards the group.

Absolutley incredible--so much so, that I was hesitant to believe it. But then I came across this story from 1996.
Then we saw him leap in the air and blood stained the water all around him. We understood that he was being attacked by sharks."

One of the crew sped to Richardson's aid in a rubber boat. When he reached him, he saw the injured man being circled by three dolphins, who leaped into the air, smacked the water with their tails and flippers, and placed themselves between Richardson and the sharks.

Wow, it's like something straight out of Flipper. Although I've also heard that dolphins can be quite violent! How do you tell which you're dealing with. And on a a side note--what the heck is a "lifesaver."