Training Dogs Vs Training Dolphins or any other species

What makes training dogs different from training dolphins or other animals?

What makes training dogs different from training humans?

We're all trainable because we all like food, right?

I suspect that what makes dogs different from humans is less substantial than the difference between dogs and dolphins. Why? Dogs and humans have a special cross-species relationship because they understand each other, or have the ability to easily learn to do so.

What facilitates this learning? Shared practice of communication via body language, shared motivators, shared social structure. (Well, human MEN naturally form and accept social hierarchies. WOMEN do not form, accept, or even recognize social hierarchies.) Dogs & humans enjoy some level of cooperative interaction and some level of independent decision-making. We are both novelty-seeking, but unsettled by novelty overload. We share similar emotional ranges, even if only humans think & feel about their emotions. We have amazing problem-solving capabilities when presented with a completely new challenge or opportunity. We both accept a market economy-- where value is affected by the reactions of others. Even our "unwanted" behaviors are oddly similar -- destruction, depression, rage, violence, rudeness, quivering, anti-social.

It's possible that, being human, we can only notice behaviors that have meaning to humans. I'm skeptical of deliberate pheromone communication, but that may be only because I have no ability to deliberately release pheromones.

Of course, I haven't worked with dolphins. Maybe this post is just a big excuse for me to find a way to train dolphins. =)