It can't be for reasons of community or any other reasons that humans do since fish do not reciprocate and the dolphins would learn quite quickly that that is the case. Dolphins are still hunted by humans in parts of the world. Yet they routinely protect and fend off sharks. Sharks have been shown to leave bloody meat alone in the presence of dolphins.

So what evolutionary reason would explain it? They seem to take the caretaker role of the ocean. What benefit could they possibly get from risking their lives for fish or humans that they don't eat and get absolutely nothing in return from?

View the original article here