I love it when animals do things that we don't expect, especially when they do things we might have species- centeredly thought were unique to humans, or when they do something that appears to be "out of character."
So that's warning enough right away that this story about dolphins isn't going to be one of the usual anecdotes about them rescuing a human from sharks (though that does apparently happen) or how they (undoubtedly) have complex communication, or have been witnessed using tools.
In fact, the only cliche I can think of about dolphins that this story will allude to is the one about their high intelligence. Because it turns out that some dolphins — the Bottlenose variety, in particular — ain't quite so bright and cuddly as we thought.