Killer Whale's a good fit for ESTJs, I think (and not as bleak). Talkative, strict social structure, but much more businesslike (i.e. less playing around, more hunting) than dolphins. Dolphins would probably be ESxP.
Also, sharks: ISTJ, and baleen whales: xxFJ (very nurturing and mom-ish).
Dunno what's up with the whale theme, but whatever.