Yes, I'm thinking about the question more because I think that the use of marine mammals is somehow different emotionally even if not different semi-objectively

Yes, I'm thinking about the question more because I think that the use of marine mammals is somehow different emotionally even if not different semi-objectively. Maybe part of it is that horse and dog are domesticated as almost extensions of people (and the pigeon doesn't have the mammalian emotional resonance). In a larger than dolphins specifically sense, it is something significant to think about since autonomous machines will be asked to perform similar tasks and since no war is "anything goes" it will be advantageous to think about how people perceive these other methods of execution.