Dolphins and such

I saw a youtube clip recently where a wild dolphin - struggling to move because of a hook and a bit of net on its pectoral fin - presented itself to some divers and made it quite clear that it wanted help getting free. It is a pretty neat video; I'm gonna embed it after the cut, along with some further musings.

Of course, after I watched this video I then spent some time clicking on related videos, and became very interested in those that showed dolphins acting altruistically, putting their lives in danger to rescue or protect other animals, including humans. There have been many documented cases of dolphins protecting humans from sharks, the most interesting one involves a group of lifeguards off the coast of New Zealand. They were swimming across a bay when a group of dolphins began to circle them, hemming them in ever closer together. The dolphins behaviour became worrisome for the swimmers who thought the cetaceans were acting aggressively towards them and might intend to hurt them. The water started to boil around them as the dolphins slapped the surface with their tails. Eventually, one of the lifeguards escaped the circle to try and get a better sense of what was happening, and it's then he noticed a great white shark beneath. Immediately it became clear what the dolphins were doing: they had formed a sort of protective boundary around the swimmers. They kept that up for 45 minutes until the shark left.

There are two ways you could follow up on such a story, or two questions you could ask. (well, I'm sure there are many questions you could ask, but these are the two that came to mind):

Why would dolphins do this? Are these truly altruistic acts?
Some say that the dolphins are picking up on the signs of distress and are then acting out of sympathy, which would be a pretty amazing fact if true, and I see no real reason to suppose these mammals are not capable of being motivated by sympathy. Maybe it goes hand-in-hand with another phenomenon; that is, doing good things for others is its own reward. There is evidence to show that these sorts of acts stimulate the reward center of human brains, causing the release of dopamine. Maybe something similar happens in some other animals as well.

What do stories like this mean for the policy of human non-intervention in nature? I mean, if the roles were reversed and a group of researchers or wildlife photographers noticed a shark attacking a dolphin, the SOP says stay clear - let Nature take her course. At what point would we make an exception to that rule? What if that dolphin just helped you? I understand why the rule is in place - the shark needs to eat to survive, and who are we to place greater value on one species over another? - but to everything there are degrees, and I'm sure there is some degree of intelligence that an animal could display that would cause us to intervene for their protection. If a fox was about to attack a rabbit and that rabbit looked up at me and said, "hey, buddy, save me!" what would I do? (assuming I didn't pass out or lose my mind at the sight of a rabbit speaking English)

Here's a related article:

http://www.ibtimes.com/raised-wolves-or-lions-or-dolphins-stories-animal-altruism-1171757