Surely, this must have some sort of important esoteric meaning beyond our ken. Dolphins aren't normal animals capable of stupid things, dolphins are little aquatic Native Americans without legs, here to condemn our materialistic society.
They heard about the Occupy movement, and decided to join in. Sadly, you can see how the Animal Welfare fascists and their mainstream media cheerleaders are treating Occupy Cape Cod.
Examining the dolphins that DID NOT SURVIVE? How about you look for TEAR GAS CANISTER MARKS.